Pakistani intelligence officials say a vehicle carrying Taliban militants has hit a roadside bomb in the country's northwest tribal region, killing five insurgents.

The officials said the incident happened Tuesday in South Waziristan, and involved insurgents linked to militant leader Maulvi Nazir. His fighters are said to cross the border to attack U.S. and NATO troops in neighboring Afghanistan.

Meanwhile, officials in southwestern Pakistan say eight Pakistani aid workers are missing and feared kidnapped.

Authorities say the aid workers went missing in Baluchistan province after distributing aid to Afghan refugees.

Baluchistan has faced an Islamist militancy, a local insurgency, and sectarian violence between majority Sunnis and minority Shi'ite Muslims.

Kidnappings in the area have been common, including five mining officials who were seized Sunday by tribal rebels.

Earlier this month, two Swiss tourists were kidnapped at gunpoint while traveling through Baluchistan in a car.