An unmanned U.S. MQ-1 Predator drone fired a Hellfire anti-tank missile into Pakistan's North Waziristan province May 7, killing Haitham al-Yemeni, an al Qaeda operative who had been under surveillance by U.S. military and intelligence personnel operating along the Afghan-Pakistani border. Al-Yemeni reportedly had replaced Abu Farj al-Libi in al Qaeda's hierarchy after the latter's May 2 capture. U.S. counterterrorism officials, believing news of al-Libi's capture would drive al-Yemeni underground, decided to strike. He is the latest in a small number of al Qaeda operatives to be taken out by a missile fired from a drone. Since Operation Enduring Freedom (OEF) — the U.S.-led invasion of Afghanistan launched in October 2001 — the United States has used Predators to strike high-value al Qaeda targets. In November 2001, al Qaeda's original No. 3 leader, Mohammed Atef — also known as Abu Hafs al-Masri — was killed in the eastern Afghan city of Jalalabad when a drone-fired missile struck the building he was in. CIA Predator pilots also reportedly used the drone to attack a sport utility vehicle suspected of carrying Taliban leader Mullah Mohammed Omar — though Omar was not in the vehicle at the time. In spring 2002, a Predator fired a Hellfire missile at three individuals in the Afghan mountains near Pakistan, one of whom appeared to be al Qaeda leader Osama bin Laden. Later examination of the bodies showed that bin Laden was not among the dead. In November 2002, a Predator strike in Yemen killed Abu Ali al-Harithi, a senior al Qaeda leader suspected of planning the October 2000 attack against the USS Cole, which killed 17 U.S. sailors in the Yemeni port of Aden. Al-Harithi was also linked to an attack against the French oil tanker Limberg in the Red Sea near Yemen in February 2002. During Operation Iraqi Freedom in March 2003, a Predator attacked and destroyed an Iraqi anti-aircraft position. On May 14, the day after the media reported the attack against al-Yemeni, the Pakistani government — not surprisingly — denied the strike had occurred. Although the government of President Gen. Pervez Musharraf is one of Washington's most valuable allies in the war on terrorism, anti-American sentiment in the country runs high. Knowledge that U.S. drones are firing into Pakistani territory could direct that sentiment toward Musharraf. The United States, however, cannot effectively operate its drones inside Pakistani airspace without the knowledge of the Pakistani government. At the very least, the use of Predators over Pakistan would have to be coordinated with the Pakistani air force — to prevent one from being shot down by the Pakistanis. As Washington expands and upgrades its fleet of drones — adding most significantly the MQ-9 Predator-B, a much-improved version of the Predator — more strikes likely will be launched against terrorists from drones.