Security forces clashed with militants in two northwest Pakistani tribal regions, killing more than 50 alleged insurgents, a paramilitary statement and a government official said Sunday.

Meanwhile, intelligence officials said that a suspected U.S. missile strike in a nearby tribal region Saturday had killed five people, but none was believed to be a foreign Al Qaeda fighter.

Pakistan's Frontier Corps, in a vague, two-sentence press release, said its paramilitary troops killed 27 alleged insurgents, including two "important commanders," in the Orakzai tribal region. The clashes followed Friday's suicide bombing in Orakzai that killed dozens of anti-Taliban tribesmen.

The statement claimed a dozen suicide bombers were among those killed Sunday by the security forces. Frontier Corps officials could not immediately be reached for more details.

Also Sunday, security forces waging an offensive in the Bajur tribal region killed at least 25 more suspected militants, government official Jamil Khan said.

Khan told The Associated Press that helicopter gunships shelled militants' bunkers overnight in the Charmang area of Bajur, killing at least 10 people. During the day Sunday, 15 more suspected militants were killed in the clashes, he said.

Insurgents in the area were fighting a local tribal militia formed to rid the area of militants. Two local tribesmen also were killed, Khan said.

Al-Qaida, a largely Arab terror network, and the Taliban, which has both Afghan and Pakistani components, have established bases in Pakistan's northwest tribal regions, where they are said to plan attacks on U.S. and NATO forces across the border in Afghanistan.

Under U.S. pressure, Pakistan has carried out military offensives against insurgents while also trying to woo various tribes to turn against extremists. The military has said its two-month-old offensive in Bajur has killed more than 1,000 insurgents.

But the U.S. has recently signaled its impatience with Pakistani efforts by apparently staging several cross-border assaults.

On Saturday, two unmanned drones were seen above the town of Miran Shah in the North Waziristan tribal region minutes before missiles hit a house near a matchbox factory, two intelligence officials said.

The officials spoke on condition of anonymity because they were not authorized to speak to the media. They said reports from local informants indicated there were no foreigners among the dead.

The latest strike brings to at least 12 the number of cross-border missile attacks believed carried out by the U.S. since mid-August. More than 100 people, most of them alleged militants, have been killed, according to figures provided to the AP by Pakistani intelligence officials.

The United States rarely confirms or denies the attacks. Pakistani leaders routinely criticize the strikes as violations of sovereignty, but those protests have had little tangible effect on the two nations' anti-terror alliance.