(CNN) -- Missiles fired by a U.S. drone killed three people in Pakistan early Thursday, Pakistani intelligence officials said, the first such attack since Pakistani Prime Minister Nawaz Sharif asked U.S. President Barack Obama to end the campaign of drone strikes.
The strike in northwest Pakistan also comes the week after human rights groups questioned the legality of the U.S. drone program in Pakistan and Yemen, documenting in detail some of the civilian casualties they say it has caused.
The identity of the three people killed in the drone attack Thursday on a compound in the thinly governed tribal area of North Waziristan hasn't yet been confirmed but they are believed to be militants, said two Pakistani intelligence officials.
Three other people were wounded in the strike near Miranshah, the main town in North Waziristan, said the officials, who declined to be identified because they weren't authorized to speak publicly about the matter.
The Pakistani government "strongly condemns" the latest drone strike, the country's Ministry of Foreign Affairs said in a statement.
North Waziristan is rife with militants and is the area where the United States conducts its most intensive drone campaign, against the Pakistani Taliban and al Qaeda operatives.
Sharif said last week that he brought up the issue of drone attacks with Obama when the two leaders met in Washington, "emphasizing the need for an end to such strikes."
Ahead of that meeting, Amnesty International and Human Rights Watch released highly critical reports on the U.S. drone program. The groups said some of the attacks may have violated international law, a charge the White House denied.
This week, members of a Pakistani family cited in the Amnesty report visited Washington to talk about a drone strike that killed a 68-year-old grandmother.
The dead woman's son and grandchildren said that by telling their story to members of Congress, they hope it will influence lawmakers to curtail the number of drone strikes in Pakistan.
The U.S. government has said strikes by the unmanned aircraft are a necessary and carefully scrutinized part of the fight against militant groups.
"The administration has repeatedly emphasized the extraordinary care that we take to make sure that counterterrorism actions are in accordance with all applicable law," White House Press Secretary Jay Carney said last week.