DERA ISMAIL KHAN, Pakistan -- U.S. missiles killed three alleged Arab militants Tuesday in a tribal region along the Afghan border, Pakistani intelligence officials said.

The officials said two drone-fired missiles hit a vehicle in the Baghar area of South Waziristan, an area that has been used by militants to cross into Afghanistan, where many are involved in fighting U.S., NATO and Afghan forces.

The two officials spoke on condition of anonymity because they were not authorized to speak to the media. The official said local informants and intercepted satellite phone conversations indicated that the militants killed were Arab.

Tuesday's strike was the second drone attack since U.S. Navy SEALS conducted a raid on May 2 that killed Al Qaeda chief Usama bin Laden in Abbottabad, Pakistan, a garrison city that also lies in the country's northwest.

The American raid on bin Laden's hideout heightened tensions between the two nations, but the United States has generally continued missile strikes even during sensitive times.

Also on Tuesday, a morning explosion outside the district court in Nowshera killed a female Pakistani police constable and a civilian, and wounded several other people, said Liaqat Ali Khan, a regional police chief.

Preliminary reports indicate that a homemade bomb was planted at a police checkpoint situated at an entrance to the court where women are scanned and searched.

Khan said he believes the court in northwest Pakistan was targeted because of its proceedings against suspected terrorists and their accomplices.

"It's definitely a terrorist attack and they chose the court because many of their accomplices are brought here to be convicted," Khan said.