The United Nations said it is deeply concerned about the situation in the northern Afghan city of Kunduz, where Northern Alliance forces have surrounded the city, trapping an estimated 15,000 Taleban fighters and their foreign allies. There are conflicting claims about whether a surrender agreement with Taleban forces in the city will be accepted.

U.S. war planes carried out strikes against Taleban positions on the outskirts of Kunduz Friday, as different factions in the Northern Alliance issued conflicting claims about whether the surrender of Taleban forces and their foreign allies would go ahead.

On Thursday, Northern Alliance Interior Minister Yunus Qanuni rejected a surrender offer reportedly agreed to by Northern Alliance commander General Rashid Dostum and the Taleban commander, Mullah Fazil.

The agreement called for safe passage for Afghan Taleban fighters and the detention of their foreign allies, several thousand mostly Pakistanis, Arabs and Chechens.

On Friday, talks continued between General Dostum and Taleban commanders in Mazar-e-Sharif, as Northern Alliance troops continued to attack Taleban positions. General Dostum said he believes the surrender of the Taleban forces and their allies was imminent.

Speaking in Kabul Friday, U.N. spokesman Eric Falt said Northern Alliance, or United Front leaders, as they prefer to be called, should allow the surrender plan to go forward. "About Kunduz, we are deeply concerned at the current situation involving the United Front and the Taleban there, "he said. "A negotiated arrangement for the surrender of the Taleban forces, if they wish to do so, will not only save both sides from further bloodletting, but also allow the United Nations and its system partners to revive the much needed humanitarian assistance operation for the Afghan people in that area."

Under the surrender plan, the foreign Taleban fighters would be placed in detention camps to await trial at a future date. Many of the foreigners are believed to be either members of, or have close links to, Osama bin Laden's al-Qaida organization.

According to reports from the city, many of the foreigners are reluctant to surrender, fearing threatened retribution at the hands of the Northern Alliance.

U.N. officials said the situation inside Kunduz is increasingly desperate, with many civilians attempting to flee, but being prevented from doing so by the forces that hold the city.