SANAA, Yemen - The United States has raised the tempo in its war against al-Qaida in Yemen, killing nine of the terror group's militants in the second, high-profile airstrike in as many weeks. The dead in the late Friday night strike included the son of Anwar al-Awlaki, the prominent American-Yemeni militant killed in a Sept. 30 strike.

Two more militants were killed and 12 wounded in other strikes.

Security officials said five strikes were carried out overnight by American drones on suspected al-Qaida positions in Shabwa and neighboring Abyan province in Yemen's largely lawless south.

Yemeni officials on Saturday attributed the recent U.S. successes against al-Qaida to better intelligence from an army of Yemeni informers and cooperation with the Saudis, Washington's longtime Arab allies.

The successes come even as Yemen falls deeper into turmoil, with President Ali Abdullah Saleh clinging to power in the face of months of massive protests.

Saturday saw the worst bloodshed in weeks in the capital, Sanaa: At least 18 people were killed when Saleh's troops fired on protesters and clashed with rivals. Witnesses estimated up to 300,000 people joined Saturday's demonstrations, the largest in the capital in several months.

"Everyone with interests in Yemen, including al-Qaida and the Americans, is raising the stakes at this time of uncertainty" said analyst Abdul-Bari Taher. "The Americans are wasting no time to try and eliminate the al-Qaida threat before the militants dig in deeper and cannot be easily dislodged."

Also dead in the Friday airstrike in the southeastern province of Shabwa was Egyptian-born Ibrahim al-Banna, identified by the nation's Defense Ministry as the media chief of the Yemeni branch of the al-Qaida.

Al-Qaida in the Arabian Peninsula, as the branch is known, is considered by the U.S. the most dangerous of the terror network's affiliates after it plotted two recent failed attacks on American soil.

Its fighters and other Islamic militants have taken advantage of Yemen's chaos to seize control of several cities and towns in a southern province. That has raised American fears they can establish a firmer foothold in the strategically located country close to the vast oil fields of the Gulf and overlooking key shipping routes.

The U.S. airstrikes pointed to Washington's growing use of drones to target al-Qaida militants in Yemen. The missile attacks appear to be part of a determined effort to stamp out the threat from the group.