Baghdad HQ in fresh rocket attack

US troops come under attack 30 times a day

Several rockets have exploded in the heavily-fortified compound used by the US-led administration in the Iraqi capital Baghdad.

The attack caused damage to vehicles but no reported deaths or injuries.

It comes as Paul Bremer, the top US civil administrator in Iraq, returned to Washington for what officials say is a "decision-making session".

The number of attacks against troops occupying Iraq has risen to 30 a day, the US army commander said on Tuesday.

When decisions need to be made, Bremer comes. Some decisions need to be made US official

Lieutenant General Ricardo Sanchez signalled that his forces would take tougher action against anti-US insurgents, warning that he would not hesitate to use any weapon at his disposal.

"The most important message is that we're going to get pretty tough," General Sanchez said. "That's what's necessary to defeat this enemy and we're definitely not shy about doing that."

Initial military reports indicated that three or four rockets had hit the "Green Zone" that contains Iraqi former leader Saddam Hussein's Republican Palace complex.

Reporters heard up to 10 explosions in two waves around 25 minutes apart. The smoke in the compound could be seen for some minutes.

"Several vehicles were damaged in the Green Zone but there have been no injuries reported at this time," a US military spokeswoman told Reuters.

Bremer leaves town

Mr Bremer cancelled a meeting with Polish Prime Minister Leszek Miller on Tuesday to fly to Washington.

The palace complex used to be a symbol of Saddam's power

"He will be updating the progress of the CPA, discussing recent attacks," said Pentagon spokeswoman Megan Grafton.

"Probably different elements in the investigation of the Black Hawk incident will be discussed, I'm sure," she added.

A Black Hawk helicopter thought to have been hit by rocket fire crashed near Tikrit on Friday, killing six soldiers.

The spokeswoman described the meetings as "routine", although a US official quoted by Reuters said: "When decisions need to be made, Bremer comes. Some decisions need to be made."

Correspondents say Mr Bremer's return comes amid growing frustration with the US-appointed Iraqi interim ruling council and what some officials say is increasing friction with Mr Bremer himself.