WASHINGTON, March 21 Ten American Muslim organisations threatened this week to cease their cooperation with the US Federal Bureau of Investigation, alleging that agency has sent undercover agents into mosques.

The groups accused the FBI of using “McCarthy-era tactics,” including covert infiltration into mosques, particularly in California.

The groups alleged that FBI agents posing as worshippers pressured Muslims to become informants, labelled civil rights advocates as criminals and spread misinformation.

The FBI declined to comment on the allegations but called the proposed move unproductive. The Muslim groups cited several incidents of the FBI targeting Muslim Americans and said that such incidents “lead us to consider suspending ongoing outreach efforts.”

The statement was issued by the American Muslim Taskforce on Civil Rights and Elections, headed by Agha Saeed, a Pakistani.

The groups described FBI informants as “agents provocateur” who try to engage Muslims into subversive conversations and then use the tapes of such conversations to force them to spy on other Muslims.

In one such incident an FBI agent threatened to make one mosque member's life a “living hell” if he did not become an informant, the Muslim Taskforce said.

Although the Task Force does not name the mosque member, another Muslim advocacy group, the Council on American-Islamic Relations, said it would seek an investigation into the Feb 21 arrest of Ahmadullah Niazi, an American Muslim of Afghan origin.

“Mr Niazi previously reported to (CAIR's Los Angeles office) and other community members that, during a raid of a friend's house, an FBI agent urged Mr Niazi to work with the agency, saying that if he refused to cooperate his life would be made a 'living hell,' “ the statement said.

Mr Niazi, a member of the Islamic Centre of Irvine, told CAIR his arrest was retaliation for his refusal, the release said.

Mr Niazi, 34, was indicted last month on charges of perjury, procuring naturalisation unlawfully, using a passport procured by fraud and making false statements.

A search warrant for Mr Niazi's California home said Mr Niazi became a naturalized US citizen in 2004 and made false statements about his past aliases and international travel.

He also made false statements about contact with his brother-in-law Amin ul-Haq, the indictment said. The indictment said Mr Haq is Osama bin Laden's security coordinator and has been labelled a “specially designated global terrorist” by the US government.

Mr Niazi has pleaded not guilty to the charges against him.

CAIR, the advocacy group defending Mr Niazi, also has had problems with the FBI.

A CAIR statement said the FBI unjustly designated this and other Muslim organizations as “un-indicted co-conspirators” in the Holy Land Foundation case. A jury convicted Holy Land Foundation leaders last year of conspiring to support terrorism and launder money for a terrorist group.

“Making this unjust designation public violates the Justice Department's own guidelines and wrongly implies that those listed are somehow involved in criminal activity,” CAIR said.