Pakistani intelligence officials say two suspected U.S. missile strikes killed at least 18 people Friday in the northwestern tribal regions near the Afghan border.

The officials say a suspected U.S. drone (unmanned aircraft) fired three missiles into a house, killing at least 10 people in a village, Zharki, outside Mir Ali, in North Waziristan province.

Local officials say five of those killed were foreign militants. The area is considered a hub for al-Qaida and Taliban activity.

Hours later, a second missile strike hit neighboring South Waziristan, killing at least eight people.

There have been about 30 similar missile attacks in Pakistan since the middle of last year, despite public objections by the Pakistani government.  These are the first ones since U.S. President Barack Obama took office on Tuesday. The Bush administration refused to confirm or deny responsibility for the strikes.

The Pakistani Foreign Ministry has welcomed Mr. Obama's appointment Thursday of a new special envoy to Afghanistan and Pakistan. The ministry said Islamabad looks forward to "enhanced and fruitful engagement" with veteran diplomat Richard Holbrooke to work toward peace and stability in the region.

Earlier, Pakistani authorities said at least five people were killed in a series of attacks in the restive Swat Valley.

Authorities say a suicide bombing at a checkpoint near the town of Mingora killed at least two Pakistani soldiers. Police say another bomb in the same general area killed at least three civilians, including a woman.

Pakistan's military has launched an offensive in the region against militants who are seeking to impose a harsh version of Islamic law.

Meanwhile, the United Nations says it is "deeply concerned about the increasing number of attacks on school buildings in northwestern Pakistan." The UN children's agency (UNICEF) says more than 170 schools have been blown up or burned down in the border regions since 2007. Five schools were destroyed on Monday.

Local Taliban militants in the Swat Valley last month said they were banning girls from attending school. The Taliban said it would kill any girls who defy the ban and blow up any school that continues to enroll female students.

Some information for this report was provided by AFP, AP and Reuters.