PESHAWAR, Pakistan — Dozens of masked gunmen blocked a mountain pass and hijacked a convoy of trucks carrying military vehicles and other supplies bound for U.S.-led forces in Afghanistan, an official said today.

Elsewhere in the country’s volatile northwest, bedeviled by al-Qaida and Taliban fighters, a suicide bomber blew himself up outside a stadium hosting athletes from around the country, killing at least two people.

Attacks are common against supply trucks that use the Khyber Pass in Pakistan’s northwest to ferry supplies to U.S. and NATO troops across the border, but Monday’s raid was particularly brazen.

Some 60 masked gunmen blocked the route at several points and assaulted the convoy, said Fazal Mahmood, an administration official for the Khyber tribal region.

Pakistani security forces traded fire with the gunmen but were forced to retreat. The militants took the trucks along with the drivers.

Mahmood blamed Pakistani militants from the Taliban movement for the attack.

“We are using all resources to trace and recover the hijacked trucks, some of which were carrying vehicles for the allied forces in Afghanistan,” Mahmood said.

Helicopter gunships were dispatched to assist in the search in the rugged region, where Pakistan’s central government has little control and militants have found hideouts.

The U.S. has praised Pakistani efforts to crack down on the militants in its semiautonomous tribal belt, and Khyber is considered particularly important because of the supply route to landlocked Afghanistan.

Today, a bomber struck outside the main gate of the Peshawar Sports Complex, which was decked with lights for the closing ceremony of the Inter-Provincial Games.

Officials in Pakistan’s North West Frontier Province had promoted the games as a way to improve their region’s battered image. Special security arrangements were made for the three-day event.

“We were so happy that despite all the apprehensions about this area that the games were ending peacefully,” said Rahat Khan, who still wore his bronze medal for boxing around his neck. “We all got a jolt because of the explosion. I am so upset.”

Malik Naveed Khan, the inspector general of police for the province, said two people were killed.

The U.S. also has carried out missile strikes in Pakistan’s northwest, and on Monday, Pakistani President Asif Ali Zardari said he expects U.S. President-elect Barack Obama to re-evaluate the need for such strikes, which generally target suspected al-Qaida and Taliban hideouts on Pakistan’s side of the Afghan border.

Zardari said in an Associated Press interview that the attacks, which have surged since August, hamper the fight against the militants — a campaign he said was succeeding nonetheless.

“We feel that the strikes are an intrusion on our sovereignty, which are not appreciated by the people at large, and the first aspect of this war is to win the hearts and mind of the people,” Zardari said.

Zardari was headed Tuesday to the United States for a U.N. conference on interfaith harmony. He was expected to meet U.S. officials and raise the issue of the missiles.

Pakistan insists it is taking on the militants, pointing to a military offensive in the Bajur tribal region that began in August and has killed 1,500 suspected insurgents.