The U.S. government has ruled out holding reconciliation talks with the leader of Afghanistan's Taliban movement, Mullah Mohammed Omar.

U.S. Defense Department spokesman Geoff Morrell said Wednesday that the Bush administration does not believe reconciliation can happen with Mullah Omar.

The remarks came a day after U.S. officials acknowledged that they are considering talks with some elements of the Taliban in an effort to reverse the deteriorating security situation in Afghanistan.

Morrell accused Mullah Omar of having the "blood of thousands of Americans" on his hands. The cleric sheltered al-Qaida leader Osama Bin Laden in Taliban-ruled Afghanistan until U.S.-led forces invaded after the September 11, 2001 terrorist attacks.

Afghan President Hamid Karzai called last month for Mullah Omar to return to Afghanistan and work for peace. The cleric is thought to be hiding along the Afghan-Pakistani border.

Morrell says such dialogue should only embrace insurgents who are willing to work with the Afghan government and renounce violence.

In other developments Wednesday, the British government said it will spend $1.1 billion on new and upgraded armored vehicles for British troops in Afghanistan.

The move is designed to better protect Britain's 8,000 troops in Afghanistan from the growing threat of roadside bombs placed by insurgents.

Also, the German government decided to scale back its contribution to U.S.-led counter-terrorism missions in Afghanistan.

The German cabinet revoked its authorization for German special forces to support U.S.-led troops fighting under "Operation Enduring Freedom," the name given to the 2001 U.S-led invasion. German troops had not taken part in such missions for the past few years.

Some German politicians had called for Germany to end its involvement in the mission, which critics blame for the deaths of Afghan civilians.

Germany still has about 3,000 soldiers serving in Afghanistan as part of a NATO peacekeeping force.

Some information for this report was provided by AFP, AP and Reuters.