A U.S. missile strike killed three suspected militants in a Pakistani tribal region near the Afghan border on Friday, a reminder of the weapons at American disposal at a time of intense strain with Islamabad, two Pakistan officials said.
Stepping up the tempo of the missile strikes is seen as one possible American option if Pakistan does not act on Washington's stepped up demands to attack Afghan militants sheltering on the Pakistani side of the border.
Last week, U.S. officials accused Pakistan's spy agency of assisting the Haqqani militant faction in attacks on Western targets in Afghanistan, the most serious allegation yet of Pakistani duplicity in the 10-year war.
The drone-fired missiles hit a vehicle near the Angore Adda border town of South Waziristan, the officials said, speaking on condition of anonymity because they were not authorized to speak to the media. The victims were associates of Maulvi Nazir, a prominent militant commander in the region, according to the officials.
South Waziristan was the main sanctuary for the Pakistani and foreign militants until the military launched an offensive there in 2009. The region has also witnessed scores of American drone attacks.
The missile attacks are seen at the most effective weapon Washington has at hitting al-Qaida and Afghan militants like the Haqqanis in the northwest. There were more than 100 such attacks last year; this year there have been around 50.
Most have hit targets in neighboring North Waziristan, considering the main militant sanctuary and the base of the Haqqani network. The Pakistani army has refused to launch an operation in North Waziristan despite U.S. demands, leading to speculation that Washington may consider more unilateral options.
Sending ground troops in could risk a confrontation with Pakistani soldiers and lead to a rupture in the alliance.
Drone strikes are unpopular, but have been tolerated by the Pakistani army.