WASHINGTON - Civilian deaths spiked in Iraq over the past week, around the same time the United Stated marked the fifth anniversary of the war and the milestone of 4,000 US troop deaths, a US military official said.

There were roughly 480 incidents of violence across Iraq last week, up five percent over the previous week, with a marked increase in high-profile suicide bomb attacks, the official said on condition of anonymity.

That level of violence was still well below peaks reached last year at the height of the surge in US forces into Iraq, though it is too soon to tell whether the increase signals a new trend, the official said.

“So far everything is still well below the worst of the worst, but we want to make sure that trend continues,” said the official, who spoke on condition of anonymity.

The US death toll for the five-year-old war hit the 4,000 mark over the weekend, with the killing of four soldiers in a roadside bombing in Baghdad.

Meanwhile Iraqi civilian deaths climbed even more steeply, by 18 percent according to the official, who put the number of civilian deaths at 71, up from 60 the previous week.

Casualties of all kinds — civilian, coalition and Iraqi security forces — have totaled about 1,190 dead so far this month in about 1,500 incidents, the official said.

“I haven’t seen anything that says the trend is definitely going up,” said the official, who acknowledged that increased suicide attacks and high profile bombings in recent weeks have raised concerns.

“Are they shifting tactics? Is it because the weather is better?” he said.

The military is particularly vigilant now as the drawdown of the extra US combat brigades sent to Iraq as part of a surge begins in earnest.

Speaking to CNN television General David Petraeus, the highest US commander in Iraq, also noted the increase in violence, including “some sensational attacks.”

David Walker, head of Government Accountability Office (GAO) the congressional watchdog organization, noted recently that “while security has improved in Iraq, a permissive security environment has yet to be achieved.”

The second of the five surge brigades has largely completed its redeployment, and three others are supposed to move out by July, bringing US force levels to around 140,000 troops. Currently, there are some 156,000 US troops in country.

As US combat power in Iraq is reduced, Iraqi security forces are supposed to take up the slack.

Petraeus has urged a pause in the US drawdown after July to see how the Iraqi security forces perform and whether further cuts in US force levels are possible.

Petraeus is expected to make more detailed recommendations on the pace and scope of the drawdown early next month in testimony to Congress.

General George Casey, Petraeus’ predecessor in Iraq and now the army chief of staff, had argued when he was in command in Baghdad that a surge in forces to Iraq would only dampen the violence temporarily unless Shiites and Sunnis reconciled.

Bryan Whitman, a Pentagon spokesman, said the surge had created the “opportunity for governments, particularly at the local level, the space and time to get some traction there.

“It’s also given us some time to further develop the Iraqi security forces, which now are increasingly taking the lead and responsibility for the security functions,” he said.

But he said US commanders were mindful of the risks of drawing down forces.

“We want to do it in a careful and deliberate way so that any repositioning that needs to take place, any turnover of responsibility to Iraqi forces is done in such a manner that we don’t have any backsliding,” he said.

© 2008 Agence France Presse