After a US drone strike killed the head of Iran’s Islamic Revolutionary Guard Corps (IRGC) General Soleimani at Baghdad’s airport on Friday, reactions have been pouring in from around the world.

US politicians were divided across party lines with some Republican politicians mainly praising the attack, while some Democrat politicians said it was "reckless," warning that it'll likely raise tensions in the region.

Iran considers the assassination of Qassem Soleimani to be an "act of war".

In reaction to the killing, the hashtag #WorldWar3 and #WWIII quickly started trending on Twitter.

According to the Pentagon, US President Donald Trump ordered the U.S. military to take “decisive defensive action to protect U.S. personnel abroad by killing "a man once referred to by Iran’s Supreme Leader Ayatollah Ali Khamenei as a “living martyr of the revolution.”

The attack is expected to draw severe Iranian retaliation against Israel and American interests. The Defense Department said Soleimani was “actively developing plans to attack American diplomats and service members in Iraq and throughout the region.”

Iran reacted quickly to the attack and appointed a new commander of the Revolutionary Guard's Quds Force: Major General Esmail Ghaani.

After Friday prayers, Iranians gathered to mourn.

Iran calls attack 'blatant violation of Iraq's sovereignty'

Iran’s foreign minister Javad Zarif said in a tweet that this was a “foolish escalation” and an “act of terrorism,” threatening the US with “consequences.”

“Perhaps America’s action was a response to the pain that this great man had inflicted on them," Zarif said.

The killing will make Iran's people more united and “will also make U.S. policies more scandalous and less effective than before," he added.

Iran’s Supreme Leader Ayatollah Khomeini also tweeted out a statement, calling Soleimani a “martyr” who, after “years of sincere and courageous struggle” finally died. He vowed “harsh retaliation.”

In a tweet on Khameini's English language account, he writes "In the Name of God, the Beneficent, the Merciful," a Quranic line that is usually used to indicate the beginning of something. Some have interpreted this line to indicate that the killing of Soleimani could be the beginning of major US-Iranian military action.

Iran also summoned the Swiss charges d’affaires, who represents U.S. interests in Tehran.

According to several analysts, Iran is interpreting the killing of its top general as a declaration of war.

While leading Friday prayers in Tehran, advisor to Khomeini and known hardliner, Ayatollah Ahmad Khatami said: "This is the time to clear the region from these insidious beasts."

A senior Iran analyst for the International Crisis Group (ICG) Ali Vaez told Euronews that "Iran is a very powerful country. It has a network of proxies and partners around the region. It can go after US and US allies' foreign interests all the way from Yemen to Saudi Arabia, to the UAE, to Iraq, to Lebanon, to Syria and Afghanistan."

He added that an all-out war between the US and Iran "would make the conflict in Afghanistan and Iraq look like a walk in the park." Vaez also reckons that the US would likely be alone if it were to go to war with Iran.

"The reality is that the US has done everything in the past few years to provoke the Iranians," Vaez pointed out.

Iranian state television called Trump’s order to kill Soleimani “the biggest miscalculation by the U.S.” since World War II. “The people of the region will no longer allow Americans to stay," it said.

For Iran, the killing represents the loss of a cultural icon who represented national pride and resilience while facing U.S. sanctions. While careful to avoid involving himself in politics, Soleimani’s profile rose sharply as U.S. and Israeli officials blamed him for Iranian proxy attacks abroad.

One Iranian Twitter user compared the assassination of Soleimani to that of Archduke Franz Ferdinand in 1914, which is considered the most immediate cause of World War I. The tweet insinuates that this could be the beginning of another world war.

Another user, who appears to be conscripted in the army, states that "poor" him is a "neutral soldier," pointing out that he expects his situation as part of the military to get much worse soon.

Other users are in line with the government response, such as this one, who promises "we will take vigorous revenge on America."

Protests in Iraq

Iraq's President Barham Salih urged Iraqis to remain united to spare the country more violence after decades of bloodshed.

Iraq's deputy parliament speaker says an emergency parliament session is set for Saturday to discuss the U.S. airstrike.

Hassan al-Kaabi says it is time to put an end to “U.S. recklessness and arrogance,” adding that Saturday's session will be dedicated to taking "decisive decisions that put an end to U.S. presence inside Iraq."

The outgoing Prime Minister Adel Abdul-Mahdi had called for an emergency session, saying the U.S. presence in Iraq is limited to training forces to fight terrorism. He described the attack that killed Gen. Qassem Soleimani and the Iraqi officials a "violation" of conditions for the U.S. troop presence.

In Iraq, protesters have taken to Tahrir Square in Baghdad in response to the killing of Soleimani. Some of the protesters approve of it. One of them, Ahmed Jabar told AP the killing of Soleimani and another Iraqi militant closely allied with Iran, Abu Mahdi al-Muhandis “will eliminate the corrupt parties which are destroying Iraq.”

Another protester said, he would prefer it if “America and Iran solve their problems outside of Iraq” since solving them within the country “will not serve our cause.”

Response in the US

US President Donald Trump said on Friday that the Iranian general was killed "to stop a war" and that the US is "ready and prepared" for any response. The US does not want a "regime change" in Tehran, he said.

Soleimani, Trump added, was plotting "imminent and sinister attacks". "We caught him in the act and terminated him", Trump said.

"His reign of terror is over", Trump announced, adding `that "a lot of lives would have been saved'' if he Soleimani had been killed years ago.

Trump had come out on Twitter earlier on Friday defending his order to kill Soleimani. He said the Iranian commander was "plotting to kill many more" Americans "but got caught."

He added, Soleimani was "both hated and feared within the country" even though Iran "will never be able to admit it.

U.S. Secretary of State Mike Pompeo is asserting that the killing was carried out in order to disrupt an "imminent" attack orchestrated by him.

"We know it was imminent," Pompeo told CNN. "This was an intelligence-based assessment that drove our decision-making process.''

Pompeo told Fox that he hopes Iran ``"will see American resolve and that their decision will be to de-escalate, to take actions consistent with what normal nations do. And in the event that they do not, in the event they go the other direction, I know that President Trump and the entire United States government is prepared to respond appropriately.''

Democratic presidential candidate Joe Biden issued a statement saying Soleimani “deserved to be brought to justice for his crimes against American troops and thousands of innocents throughout the region.”

However, the military action against him “is a huge escalatory move” which will “almost certainly” encourage Iranian attacks against the US, rather than deter them as intended, Biden continued. Trump “basically tossed a stick of dynamite into a tinderbox.”

Another Democratic candidate, Senator Elizabeth Warren called Soleimani "a murderer, responsible for the deaths of thousands, including hundreds of Americans."

However, she added Trump's reckless move escalates the situation with Iran and increases the likelihood of more deaths and new Middle East conflict."

House Speaker Nancy Pelosi said the strike was carried out “without the consultation of Congress.” In June of 2019, Pelosi had said that action against Iran “must not be initiated” without congressional approval, after Trump had approved and then reversed a decision to strike Iran over the downing of a US drone.

US congresswoman Ilhan Omar (Democrat) raised the question of whether Trump is using the conflict with Iran as a distraction for his challenges within the US.

House minority leader Lindsey Graham praised Trump’s move adding that “if Iran continues to attack America and our allies, they should pay the heaviest of prices, which includes the destruction of their oil refineries.”

Meanwhile, Secretary Pompeo tweeted a video of people marching in the street in what appears to be Iraq, saying “Iraqis - dancing in the street for freedom; thankful that General Soleimani is no more.” Euronews could not independently verify the video at this time.

Former U.S. national security adviser John Bolton is congratulating all involved for “eliminating" Iran's top military commander.

In a Twitter post on Friday, Bolton adds that “long in the making, this was a decisive blow against Iran's malign Quds Force activities worldwide. Hope this is the first step to regime change in Tehran."

Reactions from Syria

Syria has strongly condemned what it calls "treacherous American criminal aggression" that killed Iran's top general and others, warning that it constitutes a "dangerous escalation" in the region.

While Syrian President Bashar al-Assad said General Soleimani's support for the Syrian army "will not be forgotten," the country's foreign ministry said the attack reaffirms the U.S. responsibility for the instability in Iraq as part of its policy to "create tensions and fuel conflicts in the countries of the region."

The statement says the attack will only strengthen the resolve to continue down the path set "by the martyred leaders of the resistance against American interference in the affairs of the countries of the region."

Reactions from Israel

Israeli Prime Minister Benjamin Netanyahu said Trump "deserves all the credit for acting swiftly, forcefully and decisively."

The Israeli army has ordered a ski resort on Mount Hermon, on the Israel-controlled Golan Heights, to close. It took no other immediate precautions.

Yair Lapid, a leader of the opposition Blue and White Party, praised the killing and said Gen. Qassem Soleimani got “exactly what he deserved.”

The head of Iran's elite Quds Force topped Israel’s list of threats, accused of masterminding a network of enemies that included the Hezbollah militant group in Lebanon. Israel has struck Quds Force targets in Syria on several occasions.

Yoel Guzansky, an expert on Iran at the Tel Aviv-based Institute for National Strategic Studies, said Iranian retaliation against U.S. or Israeli targets was likely in the short term. Guzansky said the killing struck a huge blow to Iran and restored American deterrence in the region.

Meanwhile in Russia

Russia’s Foreign Ministry has condemned the killing and said it will increase tensions throughout the Middle East.

An unnamed diplomat in the ministry told Russia’s state-run news agency TASS they consider the killing of Gen. Qassem Soleimani “an adventurist step."

The head of the foreign affairs committee in Russia's upper parliament house called the U.S. airstrike “a mistake” that could “boomerang on its organisers.” Konstantin Kosachev in a Facebook post on Friday said the move destroyed the last hope to resolve the issues around the Iran nuclear deal.

And “Iran may accelerate making a nuclear weapon now, even if it didn’t plan on doing it before,” Kosachev said.

Vladimir Sotnikov, Director of the Russia-East-West Centre for Strategic Studies and Analysis, says the killing was a mistake,

"Maybe President Trump was not fully informed by his foreign policy advisers. In any case, he made a purely impulsive decision if it was him who made it.

The Americans made not a strategic, but a tactical mistake here. This murder sparked a new wave of fierce anti-Americanism in Iran and Trump, in his election campaign, promised to negotiate with Iran.

Here, in fact, his mistake was that the moment was chosen extremely badly, in terms of both Iran's nuclear programme and US relations with their Middle Eastern partners. The consequences of this incident are yet to follow."

China says it's 'highly concerned'

China is a close Iranian ally and a staunch opponent of the U.S. presence in Iraq. The country's Foreign Ministry spokesman Geng Shuang said on January 3 that his country is “highly concerned” and calls for all sides, especially the United States, to exercise “calm and restraint."

The spokesman added that “China has always opposed the use of force in international relations" and warned against the further escalation of tensions.

China has been among the most active countries in defying U.S. attempts to isolate Iran and cripple its economy. Last month, its navy joined with those of Iran and Russia in first-ever joint drills in the Indian Ocean.

'A more dangerous world' - Europe reacts

The first European country to react to the killing of Soleimani is France. The country's deputy minister for foreign affairs, Amelie de Montchalin said on RTL radio, "we are waking up to a more dangerous world. Military escalations are always dangerous." She added that "escalation is underway."

Macron responded later, saying that he wants to "avoid a new dangerous escalation" and called for "restraint."

The British government is urging caution, saying "``further conflict is in none of our interests.``"

Foreign Secretary Dominic Raab stated that the UK has "always recognised the aggressive threat posed by the Iranian Quds force led by Qasem Soleimani.``

The statement does not explicitly endorse or condemn the actions of the U.S., a major British ally.

Germany says the situation in the Middle East has reached ``"a dangerous escalation point'' and that conflicts in the region can only be resolved diplomatically.

German government spokeswoman Ulrike Demmer characterised the U.S. move as ``a reaction to a "whole series of military provocations for which Iran bears responsibility,'' pointing to attacks on tankers and a Saudi oil facility.

President of the European Council Charles Michel urged all parties involved to avoid further escalation "at all cost." He said, the risk of the recent cycle of violence in Iraq "is a generalised flare-up of violence in the whole region."