Kabul, Afghanistan ? A mortar shell tore through the roof of an eastern Afghan village school Thursday as boys studied, killing one child and injuring dozens, the government said.

In Kabul, British peacekeepers reported coming under fire for the third time in two weeks. No injuries were reported, though rounds came close enough to leave a bullet hole in the roof of the observation post.

Amid the violence, U.N. Secretary-General Kofi Annan urged an extension of the mandate for the British-led peacekeeping force past summer  saying too quick an exit risks chaos for Afghanistan.

The mortar attack hit a government-run boys school in Sarobi, 40 miles east of Kabul, Interior Ministry official Mohammed Azimi said in Kabul.

Family members told hospital workers the blast ripped through the ceiling of a classroom where about 35 boys were studying, said Rossella Miccio, administrator in the Kabul hospital where 19 of the injured were treated.

It was unclear whether the shell had targeted the school, or strayed. Although admitting authorities didn’t know who was responsible, Azimi blamed renegade Taliban or al-Qaida trying to sabotage Afghan leader Hamid Karzai’s new government.

“They fired the mortar intentionally,” he charged.

The area, under the control of a notorious warlord, was the site of the murder in November of four international journalists.

In Kabul, likewise, international investigators were searching for motives and culprits in Wednesday night’s firing upon peacekeepers. The lone gunman got away, but only after drawing return fire from the British.

“One gunman was seen firing, and then he was seen running away, and then he fired again,” Graham Dunlop, spokesman for the international force, said.

The shooting, like one on Feb. 20, occurred near the rocket-ruined Darulaman palace, a former residence of Afghanistan’s royalty.

The most serious shooting involving peacekeepers here occurred Feb. 16, when British peacekeepers fired on a vehicle taking a pregnant woman to the hospital. The vehicle was on the streets after curfew. The woman’s brother-in-law was killed.

The peacekeepers said then they were returning fire. The woman denied their claim, and Afghanistan’s interim administration is investigating.

Two peacekeepers involved in that shooting have since returned to Britain.

The British lead an 18-country contingent of peacekeepers in Kabul, with a total force of 4,500.

They conduct joint patrols with Afghans in an attempt to provide security in the capital, shattered by two decades of relentless war.

The United Nations is expected to decide by April whether to extend the peacekeeping force’s mandate past June.

Annan urged that it be approved, telling German lawmakers in Berlin that nations helping Afghanistan must work for “a sustainable peace, just as we aim to achieve sustainable development.”

In northern Afghanistan, meanwhile, tensions between two rival commanders underscored the difficulties facing the loosely glued-together government alliance.

Ethnic Tajik leader Atta Mohammed accused rival Gen. Rashid Dostum, an ethnic Uzbek, of sending six tanks and dozens of troops into Shulgara, 50 miles southwest of the main northern city of Mazar-e-Sharif.

A spokesman for Dostum said he knew nothing of the claim. Sporadic fighting between soldiers under the control of the two leaders has killed dozens of people in recent weeks.

Atta said he had demanded that Dostum’s local commander recall his troops to a Dostum-controlled barracks in the area. If an agreement could not be reached peacefully, Atta warned, he may attack to force Dostum’s troops back.

“We are trying to solve it in a brotherly way,” Atta told The Associated Press. “But if we cannot, then we must defend our poor people in the village.”

Atta claimed Dostum’s troops were harassing Tajiks in the area. Tajiks, Uzbeks and other ethnic groups live together in the district, which is controlled by Atta.

Earlier this week, Atta and one of Dostum’s senior lieutenants signed a peace agreement in another northwestern village where fighting the week before killed at least six people.

In other developments:

 Claims are arriving daily about the whereabouts of ex-Taliban leader Mullah Mohammed Omar, keeping U.S. search teams “very busy, day and night,” said Ahmed Wali Karzai, a military council member in Kandahar, Omar’s former stronghold.

Some say Omar’s party is in the central mountains, “then the next day they’re in Iran, then Peshawar (Pakistan),” said Karzai, brother of new Afghan leader Hamid Karzai. No trace of the fugitive cleric has been reported found thus far.

 Hamid Karzai met French President Jacques Chirac and Prime Minister Lionel Jospin in Paris, the latest stop in the Afghan leader’s foreign tours seeking cash and support for Afghanistan’s rebuilding.