Pakistan's government summoned the U.S. ambassador on Wednesday to urge an immediate halt to missile strikes on suspected militant hide-outs near the Afghan border.

Missile attacks have killed at least two senior Al Qaeda commanders in Pakistan earlier this year, putting some pressure on extremist groups accused of planning attacks in Afghanistan — and perhaps terror strikes in the West.

However, a marked uptick in their frequency has badly strained America's seven-year alliance with Pakistan, where rising violence is exacerbating economic problems gnawing at the nuclear-armed Islamic republic's stability.

Having called in U.S. Ambassador Anne Patterson on Wednesday, "a strong protest was lodged on the continued missile attacks by U.S. drones inside Pakistani territory," a Foreign Ministry statement said.

The attacks were resulting in the loss of "precious lives and property" and "undermine public support for the government's counterterrorism policies," the statement said.

"It was emphasized that such attacks were a violation of Pakistan's sovereignty and should be stopped immediately," it said.

American commanders complain that Pakistani forces have not put enough pressure on militants in its remote and impoverished border regions, an area considered a possible hiding place for Osama bin Laden and Al Qaeda No. 2 Ayman al-Zawahri.

Reflecting that frustration, U.S. military and CIA drones that patrol the frontier region are believed to have carried out at least 15 strikes since mid-August, including one that killed about 20 people at the home of a Taliban commander on Monday.

The United States rarely confirms or denies involvement.

Lawmakers on Monday passed a resolution condemning the attacks and calling on the government to take "more effective measures" to stop them.

The Foreign Ministry said it gave a copy of the resolution to Patterson on Wednesday.