KABUL — An American soldier has been captured by Taliban in Afghanistan, in the first such move since the US invaded the central Asian Muslim country eight years ago. "A US soldier who has been missing since June 30 from his assigned unit is believed to have been captured by militant forces," US military spokeswoman Captain Elizabeth Mathias told Agence France-Presse (AFP) on Thursday, July 2.

"We are using all of our available resources to find him and provide for his safe return. We are not providing further details to protect the soldier's situation and well-being."

A spokesman for the top US commander General Stanley McChrystal said the soldier was captured outside his base camp.

"It was not that the insurgents came into base and it was overrun…he left the base camp. At some point he was taken by insurgents," Rear Admiral Greg Smith told AFP.

He said the soldier was only reported missing after he failed to come on duty on June 30 and was not found after a search.

"We have high confidence that he is in the hands of insurgents."

Taliban claimed responsibility for capturing the American trooper.

"One of our commanders named Mawlawi Sangin has captured a coalition soldier along with his three Afghan guards in Yousuf Khail district of Paktika province," a Taliban commander named only Bahram told AFP.

"The coalition soldier has been taken to a safe place," he added.

"Our leaders have not decided on the fate of this soldier. They will decide on his fate and soon we will present video tapes of the coalition soldier and our demand to media."

The soldier's capture is believed to be the first case in Afghanistan since the US invasion eight years ago.

There are around 56,000 US soldiers operating in Afghanistan, according to Pentagon figures.

Major Swoop

The news about the soldier's capture coincided with the launch of a major American offensive into Taliban strongholds in southern Afghanistan.

"The intent is to go big, go strong and go fast, and by doing so we are going to save lives on both sides," Brigadier-General Larry Nicholson, commander of the Marines in southern Afghanistan, told his soldiers before the operation.

Nearly 4,000 US soldiers were ferried out before dawn by helicopters from bases into Helmand province.

US commanders say the first highly aggressive phase of the operation was set to last 36 hours.

The troops were to push south down the Helmand River valley, deep into Taliban-held areas where foreign troops have failed to establish a presence.

"Our aim is for us to be meeting local people within hours, and that's what we'll be doing for the next seven or eight months," said Nicholson.

The operation, code-named Khanjar, which means dagger in Dari and Pashtu but was translated by the Marines as "Strike of the Sword", is the first major offensive since the 2001 invasion.

"What makes Operation Khanjar different from those that have occurred before is the massive size of the force introduced, the speed at which it will insert," said Nicholson.

The operation is the first test to the Obama administration's strategy to turn the tide of the Afghan war.

US commanders have admitted that the Taliban are returning to regions they controlled before the US invasion and their strength is growing outside their strongholds in southern Afghanistan.