Rumsfeld arrived in the northern town of Mazar-i-Sharif where he met rival pro-government warlords, including ethnic Uzbek General Abdul Rashid Dostum, who has been accused of dragging his feet on efforts to disarm factional militia.

Such militia are seen as the main obstacle to extending central government rule into the unruly provinces and US officials said Rumsfeld wanted to show support for President Hamid Karzai's efforts to stabilise the region.

"The signal we are trying to send is that this is an important effort that Karzai's trying to do to extend the reach of the central government into the provinces, and particularly into the north," a senior US official with Rumsfeld said.

The defense ministry said Wednesday Dostum had given up just three tanks in a central government disarmament drive while his main rival, Ustad Atta Mohammad, with whom his forces have clashed frequently since helping the United States overthrow the Taliban in 2001, had handed over more than 50.

Rumsfeld also met Atta in Mazar and later in Kabul was to meet Karzai and commanders of the 11,500-strong US-led force pursuing Taliban, al-Qaeda and allied Islamic militants.

Afghan officials said talks with Karzai would focus on the battle against militants, efforts to rein in provincial warlords, and ways to stem Afghanistan's massive narcotics output.

On a previous visit in May, Rumsfeld said Washington had moved from major combat operations in Afghanistan to stabilization and reconstruction, a statement that has come back to haunt him.

The months that followed have seen a surge in guerrilla activity and the bloodiest period since US-led forces overthrew the Taliban in late 2001.

More than 400 people have been killed since August, including Afghan and foreign aid workers, US and Afghan soldiers, officials and police, and many guerrillas. The violence has severely hampered aid work.

Officials said Thursday suspected Taliban fighters in the southern town of Spin Boldak fired rockets at parked fuel tankers used to supply US forces, destroying one empty tanker.

Wednesday, two US soldiers were wounded, one seriously, when a renegade Afghan policeman threw a grenade at a US military vehicle in the southern city of Kandahar.

Also Wednesday, the NATO-led peacekeeping force in Kabul said it had arrested two suspected members of the Hezb-i-Islami militant group allied with the Taliban.

In Mazar, Rumsfeld met Colonel Dickie Davis, head of a British provincial reconstruction team that has been trying to ease factional tensions and push a disarmament drive.

Washington and its allies see such teams as a means to boost provincial security, but aid groups say that with only a few dozen troops each, they cannot provide sufficient protection for elections next June and vital aid work.

There are six so far and the US official said the United States intended to bring four or five more into the south and east, where the battle against militants is fiercest.

Rumsfeld's visit follows talks with NATO defense ministers to discuss ways to boost security and plug embarrassing equipment gaps limiting the alliance's ability to expand its peacekeeping force from Kabul to provide a meaningful provincial presence.

After the talks in Brussels, he said NATO might at some stage take over operations now being carried out by the US-led force, but such a move was "some distance out."