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Terrorists launched horrific attacks across three continents Friday, killing dozens of people just days after ISIS urged supporters to unleash "a month of disaster” during the Muslim holy period of Ramadan.

A man was decapitated in an apparent Islamist attack on a U.S.-owned gas factory in southeastern France, while 25 worshipers were killed and 200 wounded during Friday prayers at a Shi'ite mosque in Kuwait.

In Tunisia, gunmen sparked panic at a beach resort, opening fire and killing at least 37 people — mostly foreigners.

While ISIS claimed responsibility for the attack in Kuwait, there were no immediate claims of responsibility for the other assaults.

The Pentagon was trying to determine whether the attacks were coordinated or coincidental, spokesman Col. Steve Warren said, according to Reuters. The U.S. State Department said there was no evidence so far that that was the case.

Governments around the world condemned the attacks and went into high alert. Britain’s Prime Minister David Cameron called an emergency security meeting of officials in London, while France stepped up security at key sites and held a similar summit of defense chiefs at the Elysee in Paris.

The White House described the attacks as “heinous,” adding: “We stand with these nations as they respond to attacks on their soil.

"We are resolute and united in our shared effort to fight the scourge of terrorism," it added in a statement.

While there was little to suggest any co-ordination between the atrocities, experts noted that they came shortly after ISIS spokesman Abu Mohammad al-Adnani called on supporters to step up their activities.

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"O mujahidin everywhere, rush and move to make Ramadan a month of disaster," he said Tuesday, encouraging Islamists to "embark and hasten towards jihad.”

Charlie Winter, of London’s Quilliam Foundation, said: “Whether or not there is any link at all between these attacks, they are likely to be inspired by the same ideals.”

Olivier Guitta, security analyst with GlobalStrat, said the Tunisia attack was “a major PR coup for ISIS,” even if the group was not directly responsible.

“Terrorists, and Islamists in particular, want to target a country that has gone through the Arab Spring and has made it ‘OK’,” he said. “It is important for them that people in the West start fearing going about their business.”

Friday’s attacks showed that ISIS has the ability to inspire attacks even by supporters with no direct connection, he added.

“They have followers who are not members of ISIS that are actually listening to [messages], being inspired by them and then going on a whim and doing their terrorist actions,” he said.

In the Tunisia beach massacre, vacationers — including Western tourists — fled for cover after gunmen opened fire.

I am sickened by the attacks in Tunisia, France and Kuwait. Our countries stand together in combatting the horrors of terrorism. -David Cameron (@David_Cameron) June 26, 2015

Gary Pine, a product manager from the U.K., told NBC News that he initially thought he heard firecrackers but that "it was only when you could hear the bullets whizzing through the air that we realized it was gunfire." His 22-year-old son saw one person get shot, he said.

French Minister Bernard Cazeneuve named a suspect in the gruesome factory attack as Yassin Sahli, who had been under surveillance from 2006 to 2008 on suspicion of having become radicalized.

French President Francois Hollande called his Tunisian counterpart Friday, the Elysee said, and the pair expressed mutual solidarity in the face of terrorism.

German foreign minister Frank-Walter Steinmeier called the Tunisia attack "a cowardly assassination" of tourists," while the U.K.'s Cameron also offered condolences to the affected countries and promised "solidarity in fighting this evil of terrorism."

He said: "Islam is a religion of peace" but terrorists acted from "a twisted and perverted ideology we have to confront with everything we have."

U.N. Secretary General Ban Ki-moon condemned the "appalling" acts of violence "in the strongest terms" and said those responsible must face swift justice.

"The Secretary-General affirms that, far from weakening the international community's resolve to fight the scourge of terrorism, these heinous attacks will only strengthen the commitment of the United Nations to help defeat those bent on murder, destruction and the annihilation of human development and culture," his spokesman said in a statement.

The U.N. Security Council added its condemnation of the attacks and its condolences to the victims.

Israeli Prime Minister Benjamin Netanyahu joined the chorus of condemnation, saying that "the brutal murders in France, Tunisia and Kuwait again underscore that the enlightened world is struggling against dark forces."

"The fight against the murderous terrorism of extremist Islam requires unity, the beginning of which is the unequivocal condemnation of the murderers and those who support them," he said in a statement.