ISLAMABAD, Pakistan -- A suspected U.S. drone strike killed four militants Monday near Pakistan's northwestern border with Afghanistan while three security troops and seven militants were killed in a clash in another tribal region near the border, officials said.

Two missiles fired from the drone targeted a militant hideout in the Shawal area of Pakistan's North Waziristan tribal region, officials said. They did not elaborate.

The two Pakistani officials spoke on condition of anonymity because they were not authorized to brief the media.

Their account could not be independently verified as journalists are not allowed to work in tribal areas. American officials do not discuss the strikes, which anger many Pakistanis over civilian casualties, as well as claims that they violate Pakistan's territorial sovereignty.

The tribal region is home to both local and al Qaeda-linked foreign militants, including Afghan insurgents who focus on attacking American and NATO forces in Afghanistan.

The Pakistani army launched a major offensive in North Waziristan in mid-June. On Dec. 16, local Taliban militants responded by killing 150 people at an army-run school in Peshawar, 134 of them children.

Pakistan's civilian and military leadership has promised since the school attack to take on all militants. Pakistan has been accused in the past of tolerating certain militant groups as proxies against neighbouring Afghanistan and India.

Also on Monday, two paramilitary troops and one army officer were killed in a clash with militants during a search operation in the northwest of the country, said Suhail Khan, a senior government official in the area.

Khan said security forces were carrying out a search operation in the Banda area of the Bajur tribal region near the Afghan border when militants attacked. He said an army captain and two members of the paramilitary Frontier Corps were killed in the initial ambush and two FC troops were seriously wounded. In retaliatory action and ensuing gunbattles, seven militants were also killed, Khan said.

Associated Press writer Anwarullah Khan in Khar, Pakistan, contributed to this report.