US opens 'major Afghan offensive'

The US army says it has launched a major offensive against the Taliban in south Afghanistan's Helmand province.

The US military says about 4,000 Marines as well as 650 Afghan troops are involved, supported by Nato planes.

Brigadier General Larry Nicholson said the operation was different from previous ones because of the "massive size of the force" and its speed.

A Taliban spokesman said they would resist in various ways and that there would be no permanent US victory.

Qari Yosuf Ahmadi added that "a large number" of Taliban were in the area.

"I cannot accept the fact that 4,000 US troops have taken part in this operation," he said, quoted by the Afghan AIP news agency.

"I consider it a part of a psychological war, but if 4,000 US troops really are taking part in the operation, they will not have any permanent victory."

Meanwhile the US military reported that a soldier had gone missing in eastern Afghanistan on Tuesday. He was not part of the current operation.

Lack of capacity

The offensive is the Marines' first major operation since their recent deployment to Afghanistan.

It is also the first such operation under President Barack Obama's presidency.The operation - codenamed Khanjar or Strike of the Sword - began when units moved into the Helmand river valley in the early hours of Thursday.

Helicopters and heavy transport vehicles carried out the advance, with Nato planes providing air cover.

The BBC's Martin Patience in Kabul says the idea is that they will move into towns and villages which are under Taliban control.

With the fresh US deployments, military commanders say they are confident that they will make "significant" gains this summer, even if, as our correspondent says, a decisive victory is unlikely.

UK-led forces in Helmand launched their own operation to combat the Taliban insurgency last week, in what the Ministry of Defence described as one of the largest air operations in modern times.

Thousands of British forces under Nato command have been fighting the Taliban in Helmand since 2006, but there has been criticism that they have been overstretched and under-resourced.

Two British soldiers were killed in an explosion in southern Afghanistan on Wednesday, the UK Ministry of Defence reported.

Security aim

Southern Afghanistan is considered a Taliban stronghold.

"Where we go we will stay, and where we stay, we will hold, build and work toward transition of all security responsibilities to Afghan forces," said Brig Gen Nicholson in a statement.

At a briefing at the US military's Camp Leatherneck last week, he told personnel and embedded reporters: "One of the most critical things is to tell people why we're there, and we are going to have a limited opportunity to gain their trust."

The operation would have an initial highly aggressive stage lasting 36 hours, AFP news agency reported.

It aims to improve security ahead of presidential elections on 20 August, allowing voter registration where before there was none, Gen Nicholson said.

A US military spokesman, Captain William Pelletier, told the BBC there had been "no enemy contact" in the first hours of the operation, but one marine was slightly injured when an improvised explosive device detonated in the village of Nawa.

Nawa and nearby Garmsir - south of the provincial capital Lashkar Gah - are key targets in the operation, as the area is considered a refuge for militants and no US or Nato troops have previously operated there in large numbers.

Capt Pelletier said the US military was prepared for casualties, but stressed that "it is absolutely essential that no civilians be harmed".

Helmand Governor Gulab Mangal predicted the operation would be "very effective".

"The security forces will build bases to provide security for the local people so that they can carry out every activity with this favourable background, and take their lives forward in peace."

The Pakistan army, which is fighting its own battles with the Taliban, said it would redeploy some of its soldiers to the Chaman area bordering Helmand.

But spokesman Maj Gen Athar Abbas told the BBC that no additional troops were being sent to the region.

"Basically, it's a rearrangement of troops already present there," he said.

"It's in anticipation of movement from the other side. The area of the rearrangement is the one around Chaman in Baluchistan."

The BBC's Shoaib Syed Hasan in Islamabad says the rugged terrain makes the border almost impossible to police, and though Pakistan regularly deploys troops along the border to catch militants they are rarely successful.

As of June 2009, Nato's International Security Assistance Force had 61,130 personnel from 42 countries including the US, Canada, European countries, Australia, Jordan and New Zealand. The US is the largest contributor, providing 28,850 soldiers.

President Obama has pledged to send additional soldiers to Afghanistan, many of them redeployed from operations in Iraq, to help with training Afghan security forces and to tackle the insurgency.