Baghdad: Iraqi forces placed Baghdad under a blanket curfew throughout yesterday after US troops arrested a man suspected of plotting to attack the capital's government compound with suicide car bombs.

US troops arrested a security guard at the home of the leader of the main Sunni political bloc on Friday.

The US military said yesterday the man was suspected of planning attacks on the fortified “Green Zone'' and may have been linked to Al Qaida.

“Coalition force personnel detained an individual at the residence of Dr Adnan Al Dulaimi in Baghdad on September 29. The detained individual is suspected of involvement in the planning of a multi-vehicle suicide operation inside Baghdad's International Zone,'' the military said in a statement.

Al Dulaimi leads the Accordance Front, the largest Sunni bloc in parliament, which is also housed inside the sprawling Green Zone.

A senior official in the Front named the arrested man as Khudhar Farhan and said he was in his mid-20s and had joined Al Dulaimi's security staff about a month ago. Farhan did not have a security pass to enter the Green Zone, he said.

Report denied

Dulaimi said on Friday immediately after the raid that he expected the man to be released. He denied a report from a police source that his son was detained.

There was no official explanation for the curfew. A political source said it was linked to fears that security in the Green Zone had been compromised. He said access for all but the most senior officials had been curtailed.

The 5 sq km compound is home to thousands of people, including most senior officials and the US and British embassies.

Another senior Iraqi official said the curfew was imposed because of fears of more widespread unrest after a bloody first week of Ramadan. The curfew would remain in place until 6am today, Prime Minister Nouri Al Maliki's office said.

The US military said the curfew was the Iraqi government's decision and said such measures had proven effective in the past.