KABUL (Reuters) - Four foreign soldiers were killed in two separate clashes in Afghanistan on Saturday, officials said, the latest casualties among foreign forces in the rising violence with the Taliban.

Three soldiers with U.S.-led coalition forces were killed in a clash in the eastern province of Kunar. A soldier with NATO troops was killed along with an Afghan soldier in a gun battle with Taliban fighters in the southern province of Uruzgan.

Three other NATO soldiers were wounded in the Uruzgan incident, a spokesman for the force said.

"We know that three coalition soldiers were killed today in action in Kunar," Sergeant Chris Miller, a coalition spokesman told Reuters.

The identities of the victims were not known immediately. It was also not clear if there were casualties among the Taliban combatants.

Afghanistan is going through the bloodiest phase of violence since coalition troops overthrew the Taliban government in 2001.

More than 1,800 people have been killed in the Taliban-led insurgency, attacks by drug barons and operations of foreign forces this year alone in Afghanistan.

Saturday's toll brings the number of foreign soldiers killed to 92 since the start of the year.

The clashes are part of daily violence, but they coincided with the release of a message that the Taliban said was from their elusive leader, Mullah Mohammad Omar.

The message from Omar, who has called on Afghans to support the Taliban in their war to drive out foreign forces from the country, came on the 87th anniversary of Afghanistan's independence from Britain.

It was read to Reuters over a satellite phone by a Taliban spokesman, Mohammad Hanif.

"Celebrating Afghan Independence Day would amount to self-deception at a time when the infidel forces of the entire world have occupied the country," the message said.

"It is madness to celebrate Independence Day or to raise the national flag when the country is occupied. Rise against the infidel forces and help Taliban in the Jihad (holy war) to free Afghanistan from the slavery of the occupiers."

The whereabouts of the one-eyed Omar are not known. Afghan officials say he is hiding somewhere in neighbouring Pakistan.

The Taliban and their allies, such as the al Qaeda network of Osama bin Laden, are mostly active in southern and eastern parts of the country close to the border with Pakistan.

Most of the violence has been concentrated in southern areas, where NATO last month assumed security responsibility from coalition forces.

The move is the biggest ground operation by the alliance in its history and is aimed at allowing the U.S. military to cut down the size of its force in Afghanistan.

NATO is expected to expand its mission into the east later this year too.