U.S. marines in Afghanistan’s Helmand province have killed more than 400 insurgents since they were deployed in late April, the commander of the force said Wednesday.

Col. Peter Petronzio, who is in charge of the 24th Marine Expeditionary Unit, said the figure came from the governor of the Helmand, Gulab Mangal, and the militant casualties were sustained in intense recent fighting around the town of Garmser, a stronghold of militant activity and opium poppy production.

"The Taliban proved that they wanted to fight for Garmser and we took the fight to them, inflicted very serious casualties," Petronzio told a news conference in Kabul.

"We were a little too busy to count [enemy casualties]," he said, but added that Gov. Mangal  believed the "number is somewhere beyond 400."

"I wouldn't say that Garmser is secure, but it is stable, we are continuing to clear the area," Petronzio said.

Some 2,200 U.S. marines have been involved in combat operations in and near the town.

British and Australian troops are also deployed in Helmand.

Marines in for the duration: commander

Petronzio said NATO and Afghan forces are committed to completing their mission in an area that is an important gateway for insurgent fighters smuggling weapons from Pakistan. The marines will be replaced by British troops this fall.

"If the Taliban are waiting for us to leave, they will have a very long wait," he said.

The U.S. decision to send the marines to Afghanistan helped the Harper government win parliamentary backing in May for extending Canada’s Afghan mission another two years, to 2011.

Canada had been demanding more NATO support for its 2,500 troops, largely based in Kandahar province, west and north of Helmand.

Alert guard saved Indian Embassy

Meanwhile, India’s ambassador in Kabul has said suicide bombers that attacked his country’s embassy on Monday were trying to destroy the entire compound, and were prevented from driving their explosives-laden car inside by an alert security guard.

The guard was one of the 58 people to die in the blast, said Jayant Prasad.

Prasad said India was targeted because of its support for the Afghan government and its development work in the country.

"Some elements, some people, don’t want us to do what we are doing here," he told reporters in Kabul.

Afghanistan has made veiled accusations that military intelligence in Pakistan, India’s strongest enemy, was behind Monday's attack.

That's been angrily denied in Islamabad, and there’s been no direct comment on the allegation from either India or international officials in Afghanistan.