BAQUBA, Jan 9: A bicycle bomb killed six people in central Iraq as they ended Friday prayers at a crowded mosque used by Shias, underscoring the threat of sectarian conflict in the country.

Police later defused a car bomb outside another mosque in the same town - Baquba, north of Baghdad. The first device, a gas cylinder packed with explosives strapped to a bicycle, went off close to people praying on the pavement due to lack of space inside the small mosque.

"At the end of prayers, it exploded," a police official said. Officials at a nearby hospital said at least 39 people were injured. A US military spokesman said the car bomb outside another mosque could have caused many more deaths.

"The Iraqi police came upon the car as a routine check of the area," Captain Josh Felker said. "They found 125 kilos of TNT, four 155mm artillery shells and a remote detonation device."

Baquba, 65kms north of Baghdad, is a hotbed of resistance to the US-led occupation. US forces have mounted major operations in and around the town to capture guerillas and quell resistance.

TIKRIT OPERATION: In Tikrit, the home town of former president Saddam Hussein, hundreds of US troops stormed houses on Thursday night in the hope of capturing guerillas.

About 300 soldiers from the Fourth Infantry Division, backed by Bradley armoured vehicles and military aircraft, searched for suspects, weapons and other incriminating material in one of the biggest raids conducted by US forces in recent weeks.

US officials said they were still investigating the cause of Thursday's helicopter crash that killed all nine US troops on board near the town of Falluja, 50kms west of Baghdad and the scene of incessant anti-American attacks.

A witness said the helicopter was in flames before it went down and some reports said it could have been hit by a rocket. The deaths raise to almost 500 the number of US soldiers killed in combat or accidents since the invasion began in March.

A US military transport plane carrying 63 passengers and crew was hit by ground fire shortly after takeoff from Baghdad on Thursday, but managed to return and land safely.

The latest attacks follow a lull following last month's capture of Saddam Hussein. Spain's defence minister has said the former president had been directing guerillas before his capture.

ITALY: In a boost for the US-led forces, Italy's cabinet on Friday approved a plan to keep its 2,000-strong force in Iraq for a further six months, until June, despite the deaths of 19 Italians in car bomb attack on their base in November.

And Japan's defence chief ordered an advance team of ground troops to leave for Iraq, as the military readied for a humanitarian operation that will be Japan's biggest and most controversial overseas deployment since World War Two. -Reuters