Mr Talabani (L) says Iraqi forces are getting stronger

In a news conference in Washington with President George Bush, he said a timed pull-out could encourage terrorism.

But Mr Talabani said he hoped Iraqi forces could take some responsibility from US troops by the end of 2006.

In an interview with the Washington Post newspaper published on Tuesday, he had seemed to suggest that up to 50,000 US troops could leave this year.

An aide later phoned the newspaper to say the Iraqi president had not meant to imply specific dates.

Continued support

Flanked by US President George W Bush, Mr Talabani said he did not want to do anything without the agreement of the US, as this would demonstrate to insurgents that their resolve had been weakened.

Najaf has already been handed over to Iraq's security forces

"We will set no timetable for withdrawal. A timetable will help the terrorists, will encourage them that they could defeat a superpower of the world and Iraqi people," he said.

"We hope that by the end of 2006 our security forces are up to the level of taking responsibility from many American troops with complete agreement with the Americans."

Mr Bush said the US would continue to support Iraqi democracy.

"America will stand with the Iraqi people as they move forward with the democratic process," he said.

"At the same time, American troops will stay on the offensive... As Iraqis stand up, Americans will stand down."

In other developments:

US and Iraqi forces launch an attack on the insurgent stronghold of Haditha capturing one and killing at least four militants, according to the Associated Press news agency

Two Iraqi civilians are killed and seven others injured when a minibus explodes in Hilla, 100km (60 miles) south of Baghdad

In Baghdad a lorry driver and his assistant are shot dead while trying to deliver concrete walls to fortify polling stations for next month's referendum on the draft constitution

In a separate incident in Baghdad, five mortar rounds are fired, two of which land in the Green Zone, although they are not reported to have caused any injuries.

Najaf transfer

The US currently has about 140,000 troops stationed in Iraq.

Despite sliding public support for the US presence in Iraq, Mr Bush has refused to set a schedule for a withdrawal. He has repeated the message that the US must stay the course.

The US has been training home-grown Iraqi troops to take over from their forces to allow a phased withdrawal.

However, many observers say that the Iraqi forces are still far from capable of dealing with the ongoing insurgency.

Earlier this month the US officially handed over military control of the southern city of Najaf to Iraqi forces.

The move was the first of a planned series of security transfers across Iraq, paving the way for an eventual withdrawal of foreign forces.