The move froze any assets the five men may have in US jurisdiction, and barred Americans from conducting any transactions with them.

Oslo-based Mullah Krekar, also known as Najmuddin Faraj Ahmad, whom the Treasury said was aged either 43 or 50, was the target of an aborted "rendition" plot by the CIA three years ago, the Washington Post said Monday.

"The civilized world must stand united in isolating these terrorists," said Stuart Levey, the Treasury's under secretary for terrorism and financial intelligence, in announcing the new sanctions.

"These individuals support every stage of the terrorist life-cycle, from financing terrorist groups and activity, to facilitating deadly attacks, and inciting others to join campaigns of violence and hate," he said.

Krekar, then head of a Kurdish insurgent group, was targeted by three undercover CIA officers in the spring of 2003 as part of a possible secret operation to capture him, the Post said.

The spies left Norway by the end of the summer after Krekar was tipped off by an unidentified Norwegian official, the report said.

The CIA secretly apprehended a number of suspected Islamic radicals in Europe after the September 11, 2001, attacks.

Also among the blacklisted five was Swedish citizen Mohamed Moumou, a 41-year-old originally from Morocco whom the Treasury said has an address in London.

According to the Treasury, Moumou "was the uncontested leader of an extremist group centered around the Brandbergen Mosque in Stockholm, Sweden".

It cited reports as stating that Moumou enjoys close links to the "inner circle" of Abu Musa al-Zarqawi, Al-Qaeda's chief in Iraq who was killed in a US air strike in June.

The three other individuals were all named as Kuwaiti-based "terrorist facilitators" -- Hamid Al-Ali, Jaber Al-Jalamah and Mubarak Mushakhas Sanad Al-Bathali.