KABUL- Afghan President Hamid Karzai on Sunday visitedQatarfor talks with officials in the wealthy Gulf state that could host future peace negotiations between the Afghan government and Taliban insurgents.

With US-led NATO combat troops due to withdraw fromAfghanistanby the end of 2014, Karzai recently backed a proposal for the Taliban to open an office inDoha, the Qatari capital.

The militants refuse to have direct contact with Karzai, saying he is a puppet of theUnited States, which supported his rise to power after the military offensive that ousted the Taliban from power in 2001.

During the visit, the president was to meet Qatari officials "to discussAfghanistan's peace process and bilateral relations between the two countries", Karzai's office said in a statement.

The Afghan president had previously opposed a Taliban office in Qatar due to fears that his government would be frozen out of a peace deal involving the extremists and the US.

But in the television interview during his last visit to Qatar in March, Karzai said a Taliban office in Doha could pave the way for "direct contacts" and push forward the peace process.

Any peace talks still face numerous hurdles before they begin, including confusion over who would represent the Taliban and Karzai's insistence that his appointees should be at the centre of negotiations.

Meanwhile, President Karzai demanded that all detainees being held by British forces in the restive south be handed over within two weeks, saying that holding prisoners any longer would be a violation of sovereignty.

The British government came under fire earlier this month when it emerged that up to 90 suspected insurgents were being held without charge at Britain's main base in southern Afghanistan.

British forces are normally allowed to hold suspects detained in Afghanistan for 96 hours, but they can be held for longer in "exceptional circumstances", such as to obtain critical intelligence.

"Any continuation in detention of these prisoners by British forces will be a violation of Afghanistan's national sovereignty and laws," Aimal Faizi, Karzai's spokesman, said in a statement released late Saturday.

Faizi said that a June 22 deadline for the handover had been set and that the British embassy in Kabul had been informed.

Britain said on Thursday that it would restart transferring detainees after suspending the process last November due to claims of abuse of prisoners in Afghan custody.

Karzai has made the issue of Afghans held by foreign forces a symbol of national independence before he steps down next year and as US-led combat troops wind down more than a decade of war.

The United States handed over full control of Bagram prison in March after months of lobbying from Karzai.