They say as many as 18 people died in the attacks near the Afghan border. These mark the first such strikes since President Barack Obama was inaugurated.
White House Press Secretary Robert Gibbs repeatedly and adamantly refused to comment today on the reported U.S. air strikes.
In response to several questions, notes CBS News White House correspondent Mark Knoller, Gibbs said the strikes were something he is just not going to talk about.
The first attack hit the village of Zharki in North Waziristan, near where al Qaeda militants hide out.
Officials said a drone fired three missiles in about 10 minutes, destroying two buildings and killing 10 people. An intelligence officer said at least five victims were foreign militants.
Hours later, a second missile hit a house in the same region, killing eight more people.
The missile strikes are the latest in a barrage of more than 30 in the region since the middle of last year.
Pakistan's pro-U.S. leaders had expressed hope President Obama would halt the attacks, which have reportedly killed several top al Qaeda operatives but triggered anger at the government by nationalist and Muslim critics.
The United States rarely acknowledges firing the missiles, which are mostly fired from drones believed launched from neighboring Afghanistan, but there is little doubt it is responsible.
Islamabad routinely protests the strikes in the northwest as a violation of the country's sovereignty, but most observers speculate it has an unwritten agreement allowing them to take place, noting it would be highly damaging to be seen as colluding with Washington in attacks on its people.
Washington is pressing Pakistan to crack down on militants in the border, which it blames for rising attacks on Western troops in Afghanistan as well as violence within Pakistan.
On Tuesday as Mr. Obama was sworn-in as U.S. president, .
"We can also anticipate good hope provided Obama really takes a new course of action toward injustices the Muslim world is facing at this moment," said Qazi Hussain Ahmed, leader of the Jamaat-e-Islami, a major hard-line Islamist party.
Responding to Mr. Obama's message, Ahmed said the new president would have to reverse the "biased policies of Bush if he is really interested in seeking a new way forward with Muslim world." A new way forward, he said, can be based only on equality and justice.
Earlier Friday, a suicide attack and a roadside bomb killed two soldiers and three civilians in the Swat Valley, a one-time tourist destination close to the border region, officials said.
Pakistan has launched military offensives in parts of the northwest, but insurgents are making inroads Swat, blowing up schools, killing police and soldiers and calling for the imposition of a hardline interpretation of Islamic law.
Militancy in Swat is seen as especially dangerous for Pakistan because the valley lies away from the areas where al Qaeda and the Taliban have traditionally operated.
An indication of the difficulties facing the government, more than 1,000 hard-liners demonstrated in the capital, saying there would only be peace in Swat and other frontier regions if the government severs its ties with the United States.
"The lawlessness cannot end until the end of the pro-America policy," one speaker told the crowd gathered close to the Parliament building in Islamabad.