In the latest act against the activists, a group of Crawford residents petitioned a court on Tuesday to restrict parking in the area around the encampment outside Bush's ranch, police said.

The driver of a sports utility truck drove onto the grass verge of the road in the dark late on Monday to knock down the crosses which had been placed by activists supporting Cindy Sheehan, whose campaign against the Iraq war in Crawford has drawn widespread publicity.

On Tuesday morning, some of the crosses were still flattened or broken in the grass.

The activists said the driver was detained by police and could face charges.

Sheehan, the mother of a soldier who died in Iraq, launched her protest on 6 August after Bush began a five-week vacation at his Prarie Chapel ranch.

Sheehan, whose protest came to symbolize the rise in anti-war sentiment in the American public, is demanding a meeting with the president and is calling for the 138,000 US soldiers in Iraq to be brought home.

The woman and her supporters planted about 500 crosses in the grass by the road near to Bush' ranch to represent the now more than 1850 US soldiers killed in Iraq.

By last weekend, several hundred others had joined her protests, drawing heavy media coverage and jamming the roads of this normally languorous town of 750 in the central Texas plain.

White House officials point out that the protestors' numbers have dropped to only around 50 since the weekend.

Sheehan's son Casey was killed in April 2004, five days after arriving in Baghdad.

Bush, who said last week he sympathizes with Sheehan, has nevertheless declined to meet her.