A senior Iranian official says the attack on the Islamic Republic's embassy in London was a "very disgraceful" bonus by the British government to sweeten a multi-billion dollar arms deal with Saudi Arabia.

"This ping pong game was designed by the British government and conducted simultaneously with a visit by one of the leaders of the regional countries to London," Secretary of Iran's Supreme National Security Council (SNSC) Ali Shamkhani said on Monday in reference to the laxity and passivity of UK government and police forces in response to the attack.

A number of attackers scaled the wall of Iran's Embassy building in London on Friday and took down the Iranian flag.

According to the Islamic Republic News Agency, IRNA, British police did nothing to protect the compound during the attack.

Iran on Saturday summoned the British ambassador to Tehran over the attack on its diplomatic mission in London.

"Following an assault by a number of individuals affiliated to an extremist religious group on the Islamic Republic of Iran's Embassy in London, the country's ambassador was summoned by the director general for Europe affairs [at the Iranian Foreign Ministry] today," Iranian Foreign Ministry Spokesman Bahram Qassemi said.

The Iranian spokesperson's comments came a day after he strongly condemned the assault, urging swift action to counter the attackers.

Immediately after receiving news of the assault, Iranian Deputy Foreign Minister for Political Affairs Abbas Araqchi voiced Tehran's strong protest to Britain's ambassador to Tehran, Qassemi said.

Later on Friday, Qassemi said the attackers who had climbed on the balcony of the Iranian embassy in London were arrested, adding the spectacle was over.

He called for the trial and punishment of the perpetrators of the assault.

Iranian Ambassador to London Hamid Baeidinejad has also been threatened with death by a member of the extremist group which carried out the attack on the Islamic Republic's embassy in London.

In a post on his official Twitter account on Sunday, Baeidinejad introduced the person as Hossein Mar’ashi Qazvini, who also leveled accusations against the Iranian diplomat on social media, including allegations of murder.

In reaction to a recent rhetoric by Saudi Crown Prince Mohammed bin Salman against Iran and the Islamic resistance, Shamkhani said the Israeli regime and United States are known by regional countries as evil forces due to their attacks on Iraq and Afghanistan and the spread of terrorism in the region.

"Unfortunately, Saudi rulers throughout their political existence have created bloody borderlines in the Muslim world by promoting Takfiri groups," the SNSC secretary added.

Saudi Arabia’s crown prince has claimed that Turkey along with Iran and what he called as Islamist groups are parts of a “triangle of evil” in the region, the Cairo-based Al-Shorouk and other local newspapers reported on Wednesday.

Bin Salman arrived in London on Wednesday for a three-day trip, where the Downing Street spokesperson said the two sides had agreed to counter Iran's "destabilizing" role in the region after a meeting between the Saudi crown prince and British Prime Minister Theresa May.

Bin Salman and May also agreed on a target of 65 billion pounds ($90 billion) of mutual trade and investment in the coming years, hailing it "a significant boost for UK prosperity ... as we prepare to leave the European Union."

Iranian Foreign Ministry Spokesman Bahram Qassemi on Thursday chided British leaders over their anti-Iran remarks during the Saudi crown prince's first official foreign visit, calling on them to stop trading global peace and security for economic interests.

Qassemi condemned the "irresponsible unison" of the British and Saudi officials in accusing Iran of destabilizing the region.

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