Pakistani security officials say a U.S. drone attack in a tribal region has killed at least four people.

Authorities say two missiles were fired Saturday in the attack in North Waziristan, a region near the Afghan border considered a stronghold of Taliban and al-Qaida militants.

Drone strikes are a contentious issue between Washington and Islamabad. Pakistan says the strikes violate its sovereignty but the United States believes they are an important tool in the effort to defeat al-Qaida.

Elsewhere Saturday in Pakistan, officials say a suicide car bomber has killed five people, including at least three members of the paramilitary Frontier Corps.

Authorities say the attacker detonated his explosives near Quetta, the capital of Baluchistan province.

Baluchistan is home to various militant groups, including pro-Taliban factions, and Baluch separatists fighting a low-level insurgency in hopes of gaining political autonomy and a greater share of the profits from the region's natural resources.