SANAA, Yemen — U.S. airstrikes targeting leaders from Yemen's active al Qaeda branch killed four suspected militants, including a man suspected of involvement in the 2000 bombing of the USS Cole, officials said Tuesday.

Missiles struck a school and a car late Monday in the southern Abyan province, Yemeni security and military officials said. Large swaths of the province have fallen under the influence of al Qaeda as the militants exploit a security vacuum stemming from an uprising against President Ali Abdullah Saleh that began last year.

The U.S. considers the Yemen branch of al Qaeda to be one of the most dangerous arms of the terrorist group. U.S. aircraft have targeted al Qaeda leaders there before, notably killing Anwar al-Awlaki, a U.S. citizen, last year. The U.S. rarely comments on its air activity in Yemen.

Al Qaeda in Yemen has been linked to several attacks targeting the U.S., including that by the "underwear bomber" who tried to bring down an airliner over Detroit on Christmas two years ago.

Tribal officials in the area said the latest strike hit the militants as they were holding an important meeting at the school. Air strikes also hit targets in the surrounding mountains and a car carrying people to the meeting between the towns of Lauder and Moudia. Another car on its way to the meeting got away, the officials said.

Yemeni security officials originally put the death toll at 15 people but later lowered that figure to four. They also said 12 militants were wounded in the strikes.

They said one of the suspected militants killed was involved in the bombing of the USS Cole in October 2000, which killed 17 American sailors and injured 39 others. They identified him as Abdel-Monem al-Fathani. The attack on the U.S. destroyer was carried out while it was in the Yemeni port of Aden for refuelling .

Al-Fathani was the only one of those killed wanted by Yemeni authorities for al Qaeda activities, but he was not considered a high ranking leader in the group, the officials said.

A Western official in Washington confirmed the U.S. carried out a strike against suspected leaders from al Qaeda in the Arabian Peninsula, saying initial indications were that five people were killed. The official did not say where the strike hit or specify whether it was carried out by a pilotless drone or a warplane.

All the officials spoke on condition of anonymity because they weren't authorized to release the information.

Security across Yemen, the Arab world's poorest country, has largely collapsed during the nearly year-old popular uprising against Saleh. The militants have taken advantage of the political instability to step up operations across weakly governed remote provinces, while authorities focused their resources on putting down the protests that were inspired by other Arab Spring revolts.

Also Tuesday, armed tribesmen from the al-Mahweet province kidnapped six United Nations workers -- an Iraqi woman, a Palestinian woman, a Colombian man, a German man and two Yemeni men, said the head of the area's local council, Ali Ahmed al-Zukaym.

A UN official in Yemen confirmed the kidnapping, speaking on condition of anonymity because he was not authorized to brief reporters.

Tribes in Yemen have historically used kidnapping as a way of getting concessions from the government and hostages are ordinarily well treated before being released. Al-Zukaym said local leaders were negotiating with the kidnappers to release the six.

Yemeni Information Minister Ali al-Omrani escaped an assassination attempt when his car came under fire Tuesday outside the Cabinet building in the capital Sanaa, according to his spokesman, Abdul-Basit al-Qaidi.