AFGHAN President Hamid Karzai has said his government would not join US peace talks with the Taliban until they were led by Afghans and would suspend negotiations with the United States on a troop pact.

US officials said talks with the Taliban would begin in Doha, capital of Qatar, today, raising hopes for a negotiated peace in Afghanistan after 12 years of conflict between American-led forces and the insurgents.

However, fighting continues in the war-ravaged nation. Four US soldiers were killed in a rocket attack on the heavily-fortified Bagram base near Kabul late on Tuesday.

"As long as the peace process is not Afghan-led, the High Peace Council will not participate in the talks in Qatar," Mr Karzai said, referring to a body he set up in 2010 to seek a negotiated peace with the Taliban.

A senior Afghan official said the government was unhappy over the official status being given to the Taliban, who opened an office in Doha on Tuesday.

The Taliban has not confirmed the date for the negotiations and there was no immediate word if the talks would be affected by the Afghan government's objections.

A US delegation had arrived in Qatar for the talks, a diplomatic source said.

President Karzai said the opening of the Taliban office in Qatar showed the US had failed to honour promises made to the Afghan state about the role of that office.

The Afghan official said the office gave the Taliban "an official identity", which the Kabul government objected to.

The official said: "The US officials told us the office will be used to move peace talks forward, but not to give them an identity.

"The Taliban's flag and the banner of the Islamic Emirate was something we did not expect," the official said, referring to the Islamic Emirate of Afghanistan, the name the Taliban used during their rule.

On Tuesday, Mr Karzai had said his government would also send a team to Qatar but added the talks should quickly be moved to Afghanistan.

The president's office also said it was suspending talks on a security pact with the US that will stipulate how many American soldiers will stay in Afghanistan after most are pulled out by the end of next year.

Mr Karzai's office said: "In view of the contradiction between acts and the statements made by the United States of America in regard to the peace process, the Afghan government suspended the negotiations.

Negotiations on the Bilateral Security Agreement began this year and, if completed, will set out how many US bases and soldiers will remain in Afghanistan once Nato ends combat operations by December 2014.

The Afghan official said: "The suspension of the talks will continue until there is clarity from the United States."

The Taliban have until now refused talks with Kabul, calling Mr Karzai and his government puppets of the West. However, a senior Afghan official said earlier the Taliban were now willing to consider talks with the government.

Despite the Afghan government's anger, the commitments by the US and the Taliban to meet this week have raised hopes for a negotiated peace.

The Taliban have said they want a political solution that would bring about a just government and end foreign occupation of Afghanistan.

The first signs of optimism in peace efforts for many months comes as the US-led war effort reaches a critical juncture.

The Nato command in Kabul on Tuesday completed handing over lead security responsibility to Afghan government forces across the country.

US President Barack Obama, travelling in Europe, welcomed Mr Karzai's announcement that Afghan forces would soon take responsibility for security from the US-led Nato force.

"We do think that ultimately we're going to need to see Afghans talking to Afghans about how they can move forward and end the cycle of violence there so they can start actually building their country," Mr Obama said at a joint news conference in Berlin with German Chancellor Angela Merkel.

Earlier, President Obama cautioned against expectations of rapid progress in talks with the Taliban, saying the peace process would not be easy or quick.

After a G8 meeting in Enniskillen in Northern Ireland, he said: "This is an important first step towards reconciliation; although it's a very early step. We anticipate there will be a lot of bumps in the road."

US officials said that, in the talks in Doha, the US would stick to its insistence that the Taliban break ties with al Qaeda, end violence, and accept the Afghan constitution, including protection for women and minorities.

The Taliban are expected to demand the return of former senior commanders now detained at the US military prison at Guantanamo Bay in Cuba, a move opposed by many in the US Congress, besides the departure of all foreign troops.

However, the US hopes to keep a force, of an as yet undetermined size, in the country after the end of the Nato combat mission.