A roadside bomb killed five Afghan border security guards Sunday on a heavily used road in southern Afghanistan.

Gen. Abdul Raziq, a border security commander, said the bombing occurred before dawn in the Spin Boldak district of Kandahar province, near the Pakistan border.

The attack comes amid reports that nearly a dozen militants suspected of having ties to high-ranking Taliban members were detained in separate operations Sunday, underlining the security struggle in the country's south.

The district is in a volatile area that has been patrolled mostly by border security police. U.S. troops moved into the region in July.

Meanwhile, NATO said in a statement that forces detained several militants with links to the Taliban on Sunday.

Several people were detained in Kandahar province, including a suspected militant who NATO says was involved with homicide bombings in the area and has links to several senior local Taliban leaders.

South of Kabul, an Afghan-international security force detained several militants near the village of Kashimiri Balat while pursuing an alleged Taliban member involved in the weapons trade, it said. The joint security force recovered a number of weapons, including grenades and a military-grade night vision device.

In another operation south of the capital, a joint force detained several suspected militants, including a Taliban commander linked with several local Taliban leaders.