Eyewitnesses say the bodies are still lying in the open

After a fierce battle near the southern Afghan border town of Spin Boldak, Afghan officials sent more than 20 bodies over the border, saying they were not Afghans. They were among at least 46 people killed in the battle.

But Pakistan has refused to accept them, saying they are not Pakistanis and warning that the Afghan refusal to take back the bodies may spark tension in the border region.

About 40 suspected Taleban and six government soldiers were killed in the fighting that lasted more than six hours, district governor Said Fazaluddin Agha said.

Pakistan has nothing to do with the affairs across the border Pakistani border police official

Correspondents say that in recent months, some senior Afghan officials have accused Pakistani intelligence of helping the Taleban to regroup.

The government in Islamabad denies the allegations, saying that it is actively co-operating with the American authorities to eliminate the remnants of Taleban and al-Qaeda.

The latest clash - the biggest in more than a year - came as Afghan President Hamid Karzai prepared to meet UK Prime Minister Tony Blair for talks on reconstruction efforts in the troubled country.

Resurgence?

"Afghan officials brought the dead bodies in three pick-ups at 0730 (0230 GMT) and went back after throwing them in an open place," said a Pakistani border police official quoted by the AFP news agency.

"Pakistan has nothing to do with the affairs across the border," the official added.

Eyewitnesses say the bodies are still lying in the open near the Pakistani town of Chaman, with no one coming forward to identify or claim them.

Sporadic fighting around Spin Boldak had been going on for about a week, with suspected Taleban fighters staging hit-and-run attacks on local forces, the BBC's Kylie Morris reports from Kabul.

But on Wednesday, the battle escalated in Nimakai, a town about 10 kilometres (six miles) north of Spin Boldak, as well as nearby Populzai and Hassanzai.

"We were trying to find these Taleban and we got a tip that they were hiding in these villages," Mr Fazaluddin Agha said.

The local forces numbering 50 called for reinforcements and another 100 soldiers were sent - but no international troops, he said.

In recent days, the US-led coalition has conducted operations near the town of Gardez, where they captured four men who they believed to be connected to the Taleban.

The campaign was launched on the basis of local reports that a senior Taleban official had moved back into the area, accompanied by Arab fighters.

There has also been persistent fighting in recent weeks in the north between key factions.

London talks

During his London visit, Mr Karzai was expected to discuss plans to draft a new constitution in his country.

Mr Karzai (right) needs help rebuilding his country

He was also set to urge the international community to provide more financial assistance to Afghanistan.

The UK Government has given its support to a provincial reconstruction team in the northern capital of Mazar-e-Sharif and is expected to send 50 military personnel to the turbulent city.

The UK and Afghan leaders will also discuss drugs.

Afghanistan is the world's leading exporter of opium, and its farmers supply 90% of the heroin that hits Britain's streets.

Britain has played a leading role in the counter-narcotics campaign to stop Afghan farmers cultivating poppies.

But this year is still expected to be a bumper crop.