Ten suspected militants were killed Thursday in a pre-dawn drone strike on a compound in a tribal district in northwestern Pakistan, a local tribesman and security official said.

In Thursday’s attack, the second by a U.S. drone in 24 hours, two missiles struck a house in the Mirali area of North Waziristan, the officials said. Initial reports said eight militants, including five “foreigners,” were killed and several wounded.

The death toll was later increased to 10, according to a security official in the area who spoke on the condition of anonymity. He identified five of the militants as “Central Asian nationals linked to al-Qaeda.”

The back-to-back drone strikes come during a difficult time in the counterterrorism alliance between the United States and Pakistan. Pakistan has publicly demanded an end to U.S. drone strikes, and the government has repeatedly found itself at odds with the Obama administration.

Perhaps the most urgent issue has been Pakistan’s closure of its borders to NATO supply convoys bound for Afghanistan — an action it took in November in retaliation for an errant U.S. airstrike that killed 24 Pakistani soldiers last year.

This week, tensions flared again as a Pakistani court imposed a 33-year sentence on a doctor who assisted the CIA in the hunt for Osama bin Laden. The doctor had conducted a vaccination program in the Pakistani city of Abbottabad to determine whether, on the basis of DNA taken from his relatives, bin Laden was living there. The court convicted him of treason.

U.S. lawmakers, alarmed at the prison sentence for a doctor they view as a patriot, condemned the decision.

“Americans will have great difficulty knowing that one year after the United States found and killed the most notorious terrorist in modern history hiding on Pakistani soil, the most visible action being taken to find out how he came to be in Pakistan is the conviction in a Pakistani court of the physician who helped the United States identify Osama bin Laden,” Sen. John F. Kerry (D-Mass.), chairman of the Senate Foreign Relations Committee, said in a statement Thursday.

In response to the court ruling, Senate appropriators voted Thursday to withhold $33 million in assistance to Pakistan until it releases the physician.

The money, to be deducted from $250 million allotted to fund Pakistani purchases of U.S. military equipment in fiscal 2013, will be restored when the doctor, Shakil Afridi, “has been released and cleared of all charges,” according to an amendment introduced by Sen. Lindsey O. Graham (R-S.C.).

The Senate committee has also reduced to $50 million an $800 million administration request for a fund that reimburses Pakistan for its military efforts against terrorists.

The fund has been virtually frozen for the past two years during a series of U.S.-Pakistan disputes.

Pakistan says it has $3 billion in unpaid counterterrorism expenses, while the United States puts the figure closer to $1 billion. The fund was already slated to be eliminated in the new budget as the United States begins making Pakistani-demanded payments for the use of its highways and border crossings to ship military goods into Afghanistan.

The transit was virtually free before Pakistan closed the crossings, and the two sides have not yet come to an agreement over how much it should cost.

The administration has also requested about $1 billion in economic assistance for Pakistan next year.

Leiby reported from Islamabad, Pakistan. Staff writer Karen DeYoung in Washington contributed to this report.