George Galloway with Iraq's deputy prime minister Tariq Aziz in 1999
George Galloway has been suspended from the Labour Party pending "internal party investigations".
The left-winger had come under fire for remarks he made at the height of the Iraq war when he branded Tony Blair a "wolf" and made comments seen as urging Arabs to rise up against the coalition forces.
He had also said, in an interview with Abu Dhabi television, that British troops should refuse to follow what he said were illegal orders.
Mr Galloway immediately hit back at the suspension, describing it as "completely unjust" and "prejudicial" to his libel action against the Daily Telegraph.
He said he stood by every word of the Abu Dhabi interview and told BBC Radio 4's PM programme: "Have we really come to a stage where a member of Parliament is silenced and politically destroyed because they spoke out against the majority of the party?
"Is that what free speech and parliamentary democracy is going to be in the new Blair era?"
The MP was informed of his suspension in a letter from David Triesman, Labour's general secretary.
A spokesman for the party said the suspension followed complaints that Mr Galloway had acted contrary to Rule 2A.8 by "bringing the Labour Party into disrepute by behaviour that is prejudicial or grossly detrimental to the party".
According to party officials, complaints had been received about an interview Mr Galloway did on 28 March with Abu Dhabi TV in which he "seemingly invited other Arab nations to fight against the British Army".
In the same interview, the MP described Mr Blair and US President George Bush as "wolves", although it is understood that this remark is not at the centre of the complaints.
It is grossly prejudicial, it is absolutely unjust, unfair and after 35 years a member of the Labour Party, you can imagine I feel deeply aggrieved
The Labour spokesman said there had been other complaints about similar remarks in an interview the MP gave to the ITV News Channel on 1 April.
The spokesman said after "careful consideration and in view of the need to protect the party's reputation", Mr Triesman had given Mr Galloway notice that he is suspended from holding office or representing
the party pending the outcome of internal party investigations.
The party's inquiry is to be conducted by Chris Lennie, the party's deputy general secretary.
The spokesman said Mr Triesman had taken note of Mr Galloway's claims in interviews that he would, in certain circumstances, stand for election against an official Labour candidate.
Mr Triesman understood that the MP has or intends to issue proceedings in respect of some, if not all, newspaper reports alleging financial links with the former Iraqi regime, the spokesman said.
He will "keep open the option of referring any further appropriate matter" to Mr Lennie for investigation should it appear necessary to do so, the spokesman added.
In recent days Mr Galloway has been under the spotlight after the Daily Telegraph printed allegations about his relationship with the fallen Iraqi regime.
Its claims, which Mr Galloway strongly denies, are to be investigated by Parliament's standards watchdog Philip Mawer.
The commissioner will investigate whether the MP was paid money which was not declared to the Commons fees office.
The investigation comes after Conservative MP Andrew Robathan wrote to Mr Mawer following the Daily Telegraph claim that Mr Galloway accepted up to £375,000 a year from Iraq.
'Right and duty'
Mr Galloway told PM that the suspension by Labour and investigations by the Charity Commission and the Parliamentary Standards Commissioner were all controlled by the Labour Party.
"They are designed to undermine and to prejudice my legal rights in the High Courts where I am suing the Telegraph and the Christian Monitor for libellous allegations against me.
"It is grossly prejudicial, it is absolutely unjust, unfair and after 35 years a member of the Labour Party, you can imagine I feel deeply aggrieved," he said.
Mr Galloway said he had a "right and a duty" to speak his mind, "especially in a time of war and especially when millions of Labour supporters agreed with me".
Mark Craig, chairman of Mr Galloway's constituency Labour Party, said the MP still had his full support.
"I cannot believe this has happened. The party has taken a wrong move," he told BBC News 24.
But Labour MP David Winnick said he was not surprised at Mr Galloway's suspension.
"I do not believe there will be many tears at the Labour Party at his leaving," he said.