A suspected U.S. missile strike killed up to 20 people in northwest Pakistan on Monday, officials said, the latest salvo in an intensifying assault on militant hide-outs near the Afghan border.

In other violence raging across Pakistan frontier zone, a car bomb killed two people in Quetta and a suicide attacker demolished a checkpoint, injuring eight police and troops.

The reported missile strike occurred in South Waziristan, part of a belt of tribally governed territory considered a possible hiding place for Usama bin Laden and Al Qaeda No. 2 Ayman al-Zawahri.

Two intelligence officials, speaking on condition of anonymity because they are not authorized to speak to media on the record, said the targeted house in Mandata Raghzai village belonged to a lieutenant of local Taliban chief Maulvi Nazir.

The officials, citing reports from agents and informers in the area, said militants cordoned off the scene and the identity of the 20 bodies pulled from the rubble was not immediately clear.

Missile strikes into Pakistan's border region have escalated sharply amid complaints from American commanders that Pakistani forces are not putting enough pressure on militant strongholds on their territory.

U.S. military and CIA drones that patrol the frontier region are believed to have carried out at least 15 strikes since mid-August. The United States rarely confirms or denies involvement.

The tactic has killed at least two senior Al Qaeda operatives in Pakistan this year and ramped up the threat to groups suspected of plotting attacks on Western troops in Afghanistan and terror strikes in the West.

However, it has also put severe strain on Pakistan's seven-year alliance with the U.S., especially since stalwart American ally Pervez Musharraf stepped down as army chief and president.

Pakistan's new leaders have protested the missile strikes — as well as a highly unusual raid by helicopter-borne commandos in September — as unacceptable violations of their sovereignty.

The attacks, they argue, are fueling the militancy destabilizing Pakistan and undermining the nuclear-armed nation's already faltering economy. Pakistan is seeking International Monetary Fund assistance to prevent it from defaulting on its foreign debt.

The car bomb in Quetta exploded in a parking lot near government buildings and the Iranian consulate, setting fire to a string of vehicles. Police said a rickshaw driver and another unidentified person died and that 10 others were injured.

There was no immediate claim of responsibility.

Quetta is the capital of a region dogged for years by a low-level insurgency seeking greater autonomy. It is also considered a hub for Taliban militants operating in neighboring Afghanistan.

Further north, a suicide bomber rammed an explosive-laden car into a security post in the Mohmand tribal region late Sunday. The army said the blast killed one civilian and injured 13 other people, including 11 troops and police.

Security forces are already battling militants in two areas of the northwest. In the Bajur region adjoining Mohmand it claims to have killed 1,500 insurgents in a two-month offensive that has drawn U.S. praise.

Yet many Pakistani are weary of a war they believe is being fought at America's behest and the government has offered to negotiate with any militant group willing to renounced violence, regardless of their ideology.

"There is an increasing realization that the use of force alone cannot yield the desired results," Pakistani Foreign Minister Shah Mehmood Qureshi told a gathering of Pakistani and Afghan tribal elders.

The meeting in Islamabad was part of a dialogue process begun last year in hopes that it could ease strained relations between Pakistan and Afghanistan, both crucial allies of the U.S.

Afghan President Hamid Karzai has repeatedly accused Pakistan, which backed the Taliban takeover of Afghanistan prior to the Sept. 11, 2001 attacks on America, of secretly continuing to aid the militants as a way to exert influence over its poorer neighbor.

Pakistan denies the charge. However, it has also seized on recent indications that Afghanistan's government is also seeking talks with the Taliban to press for compromise.

Talks should be open to "sons of the soil willing to forsake the path of violence. With a patient air, we must listen to them," Qureshi said. Both Afghanistan and Pakistan "need a healing touch," he said.