SANAA, Yemen: An airstrike killed two suspected al-Qaida militants in Yemen on Friday while tribesmen with links to the group were believed to be behind an attack on an oil pipeline elsewhere in the country, Yemeni security officials said.

Officials and residents suspect that the strike in the southeastern province of Hadramawt was carried out by a U.S. drone. Washington considers al-Qaida in Yemen the group's most dangerous branch and has carried out drone strikes that have killed militants there before.

Yemeni security officials said the two men were killed while riding a motorcycle. The officials spoke on condition of anonymity because they were not authorized to speak to the media.

The attack around the town of Shehr comes just days after another suspected drone strike in the same area killed five al-Qaida militants. The Interior Ministry said among those killed in that attack was Abdullah Bawazir, the chief architect behind a mass prison break last year that freed dozens of fighters who then took arms against the government and helped administer al-Qaida rule in the south.

The group overran entire towns and villages in southern Yemen last year by taking advantage of a security lapse during nationwide protests that eventually ousted the country's longtime ruler. Backed by the U.S. military, Yemen's army was able to regain control of the region but al-Qaida militants continue to launch deadly attacks against Yemeni security forces that have killed hundreds.

On Monday, another suspected U.S. drone strike killed two militants in the southern town of Radda in Bayda province, which was also briefly overrun by al-Qaida militants earlier this year.

Elsewhere in Yemen, al-Qaida linked tribesmen were believed to be behind an attack on an oil pipeline in the northeastern province of Marib, just hours after the line was fixed on Friday. Tribesmen from Marib have also attacked power stations in the past.

The government has carried out deadly strikes against the tribesmen in recent weeks, but has failed to stop the acts of sabotage.

The more than 430 kilometer-long (260 miles) oil pipeline carries around 100,000 barrels of oil per day. The government said the acts of sabotage this month alone have amounted to $310 million in losses to the impoverished Arab nation.

Some tribal chiefs are also suspected of being allied with former longtime President Ali Abdullah Saleh. The attacks appeared to be aimed at undermining the new government.