A statement by the administration of the Pakistan's tribal region bordering Afghanistan also said that between 10 and 12 foreign extremists had been invited to dinner at the village hit in Friday's attack.
Pakistani officials have said Ayman al-Zawahri, Osama bin Laden's top lieutenant, was invited to a dinner in the village to mark an Islamic holiday but did not show up and sent some aides instead.
Meanwhile, a threatening phone call that forced the United Nations to close offices in southwestern Pakistan said al Qaeda would attack the world body's offices there, the top U.N. official in Pakistan said Tuesday.
The phone call was received Monday by the U.N. High Commission for Refugees, and the United Nations closed all offices in the southwestern province of Baluchistan on that day and Tuesday, said Jan Vandemoortele, the U.N. Humanitarian Coordinator in Pakistan.
"Al Qaeda was mentioned twice in the phone call," Vandemoortele said. "It was found to be a credible threat."
The airstrike strained ties with a key U.S. ally in the war on terror and could provoke more anti-American fanaticism in Pakistan, analysts say.
Friday's alleged CIA mission in the Bajur tribal region, which Pakistani officials say missed its target and killed 17 people including women and children, also undermined the fragile goodwill cultivated in Pakistan by generous U.S. relief in the wake of October's earthquake that killed over 80,000 people.
"This will consolidate anti-American sentiment," said Talat Masood, a retired Pakistani general and political analyst.
Thousands rallied across Pakistan over the weekend against the United States and Pakistani President Gen. Pervez Musharraf, who walks a political tightrope by maintaining close ties with Washington in an Islamic country where the U.S.-led wars in Afghanistan and Iraq have been extremely unpopular.
Pakistan's The News newspaper warned in a Monday editorial that the missile strike could stir more extremism — particularly in tribal areas near the Afghan border, long a recruiting ground for jihadists.
"Episodes such as the Bajur tragedy, for a province where the situation is already delicate, can supply an excellent new cause to the fanatics," it said.
The attack was the third suspected U.S. strike in less than two months inside Pakistan, which says it does not allow American forces based in Afghanistan to cross the border in the hunt for members of the Taliban and al Qaeda.
Pakistani intelligence officials have described the latest strike as a CIA attack, probably carried out by missiles from a drone aircraft.
Pakistani intelligence officials say 12 militants may have been killed, but a U.S. counterterrorism official said it's unclear whether Ayman al-Zawahri, al Qaeda's No. 2 leader, was among the dead.
But Pakistan clearly feels the attack was a step too far. It lodged a diplomatic protest over the incident Saturday, calling it a "loss of innocent civilian lives." The Pakistani government previously issued a protest after tribal leaders claimed U.S. helicopters opened fire on a cleric's home in North Waziristan on Jan. 7, killing eight people.
On Tuesday, Prime Minister Shaukat Aziz said Pakistan "cannot accept any action within our country" like the U.S. missile attack, but stressed he would press ahead with an official visit to Washington later Tuesday.
"The relationship with the U.S. is important, it is growing. But at the same time such actions cannot be condoned," Aziz said at a joint news conference in Islamabad with former President George H.W. Bush.
In a speech shown Sunday on state-run Pakistan Television, Musharraf did not address the airstrike directly, but he warned his countrymen not to harbor militants, saying it would only increase violence inside Pakistan.
Despite suspicions that al Qaeda and Taliban figures enjoy some degree of sanctuary inside Pakistan, the country's law enforcement agencies have arrested more than 700 al Qaeda suspects in the past four years — including top figures, among them the mastermind of the Sept. 11 attacks, Khalid Shaikh Mohammed.
Secretary of State Condoleezza Rice on Sunday paid tribute to Pakistan's role in fighting terror, but analysts say any boost the United States received in public opinion by providing helicopters and hundreds of millions of dollars in aid in the aftermath of the Oct. 8 earthquake has been squandered.
"This has done great harm to the American image in Pakistan and neutralizes the good deeds done in the earthquake relief," said Khalid Mehmud, senior research analyst, Institute of Regional Studies in Islamabad.