Updated

Fighting erupted Wednesday between rival warlords who both claim allegiance to the government of President Hamid Karzai (search), and an official of one of the warring groups said as many as 60 people were killed and scores more wounded.

A commander for the other side, however, said only three people had been killed in a battle outside the northern city of Mazar-e-Sharif (search). It was impossible to verify either account.

Afghan Interior Minister Ali Ahmad Jalali said he would travel to Mazar-e-Sharif later Thursday with a team of government officials to find out why there is fighting between two warlords who both claim allegiance to the government of Karzai.

The fighting came as a deal was signed in the capital of Kabul between the Afghan government and the United Nations that paves the way for teams of U.N. and Afghan personnel to deploy to cities across Afghanistan to start a much-delayed program to disarm militiamen loyal to warlords.

Gen. Abdul Sabur, a spokesman for warlord Atta Mohammed's Jamiat-e-Islami faction, told The Associated Press by phone that hundreds of rival soldiers were massing around Mazar-e-Sharif.

He said fighters loyal to northern Uzbek (search) commander Abdul Rashid Dostum began battling Atta's supporters about midday, and the battle continued late into the night.

Sabur said 60 people were killed in that fighting, which involved tanks, heavy artillery and other weapons.

"The fighting is very intense," Sabur said. "People are very scared. Shops and markets have all closed."

A second Jamiat spokesman, Ashraf Nadim, said fighters loyal to Dostum launched a separate attack in Maimana city, in the neighboring northern province of Faryab. He said it was not clear how many people had been killed there.

However, Syad Noorulla, one of Dostum's commanders, told AP that Atta's forces ambushed his troops about 30 miles west of Mazar-e-Sharif and killed three of his militiamen and wounded four.

He said the situation was tense across the region, but that there was no other fighting.

Foreign Ministry spokesman Omar Samad said the government did not know the extent of the clashes and had heard varying death tolls ranging from just a few to several dozen.

"These battles are the worst we've seen in months," he said. "It needs to be contained before it spreads."

The two sides have clashed repeatedly in the past two years, though they are nominally both loyal to Karzai's central government. Countless efforts by the United Nations and the Afghan government to mediate a peaceful resolution have failed.

It was not clear what sparked the latest fighting.

Disarming the tens of thousands of militiamen is essential if the Afghan government is to be able to build and deploy a national army to maintain security. It is also an important step if a NATO-led peacekeeping mission is to expand to regions outside Kabul.

However, convincing the warlords, many of whom are also provincial governors, to agree to surrender their weapons will be a major challenge. Some of them are allegedly involved in drug trafficking and other crimes and may see little benefit in giving up the arms that keep them in power.

The first disarmament team is expected to be deployed to the northern city of Kunduz on Oct. 25. Teams are then scheduled to be deployed to the cities of Gardez, Mazar-e-Sharif and Kabul later this year.

Attempts last year to disarm the two militia groups loyal to Atta and Dostum largely failed.