UK police arrest 9 men suspected of terror offenses in London

The men, ages 22 to 51, were detained Thursday morning in London on suspicion of being members of a banned organization, supporting a banned organization and encouraging terrorism. They were taken to police stations in central London and remain in custody, a police statement said.

Eighteen homes, business premises and community buildings across London are being searched as part of the investigation. Officers are also searching a home in Stoke on Trent in the English Midlands.

"These arrests and searches are part of an ongoing investigation into Islamist related terrorism and are not in response to any immediate public safety risk," said the Met Police statement.

Police did not give the identities of those arrested nor name the banned organization concerned.

But the UK's Press Association news agency cited sources as saying radical British cleric Anjem Choudary was among those arrested.

Choudary, who was a co-founder of the banned UK Islamist group Al Muhajiroun, told CNN last month that the world had been split into two camps.

There's a "camp which believes that sovereignty and supremacy belongs to God. They are the Islamic State, at the head of which is Abu Bakr al-Baghdadi," Choudary said. "In the other camp you have those people who believe sovereignty and supremacy belongs to man. At the head of that camp is Barack Obama."

"I believe this Islamic State will spread, rapidly, and I believe it will be in Europe and even America within decades."

Cameron lays out plans to counter UK jihadi threat

Parliament recalled

UK Prime Minister David Cameron called Wednesday for Parliament to be recalled Friday to debate the nation's response to a request from the Iraqi government for airstrikes to support operations against ISIS in Iraq.

Speaking in New York, where he's attending the U.N. General Assembly, Cameron said he was convinced that ISIS is "a direct threat" to Britain and that the nation should join international efforts against the group in Iraq.

"What we are doing is legal, it is right, it does not involve British combat troops on the ground. But as ever with our country when we are threatened in this way, we should not turn away from what needs to be done," he said.

"I am confident we will get this through Parliament on an all party basis, and I think it is right for our country to be united at this time."

Any action against ISIS in Syria would require a separate parliamentary debate and vote, he said.

Terror threat level raised

The Home Office has listed 60 international proscribed terrorist organizations as of August 2014.

They include networks such as ISIS and al Qaeda, as well as UK-based groups such as Al Muhajiroun, which emerged in 1996 and has operated under a range of other names since being disbanded in 2004.

The UK Home Office last month raised its terror threat level from "substantial" to "severe."

The government also announced new measures to combat the threat from Islamist extremism, including a radical new measure to ban Britons from coming home once they join jihadi ranks abroad.

UK authorities estimate that 500 Britons have gone to Syria and Iraq to fight with Islamist groups.