Suicide bomber kills police officer in Pakistan

ISLAMABAD (Reuters) - A suicide car-bomber blew himself up near a highway toll booth east of Pakistan's capital, killing a policeman, police said on Sunday.

Militants have been attacking police and other targets in Pakistani towns and cities while the army battles Taliban fighters in their stronghold near the Afghan border.

The army assault in South Waziristan is seen as a test of the government's determination to tackle Islamists. The campaign is being closely followed by the United States and other powers embroiled in Afghanistan's growing conflict.

In the latest attack, the bomber detonated his explosives when police stopped his car at a motorway exit about 145 km (100 miles) east of the capital, Islamabad, for a search late on Saturday, a senior police officer said.

"Two people were traveling in the car. One man got out and walked away a few yards. When police approached to search the other man behind the wheel blew himself up," said police officer Mohammad Ali Babkhel.

Police arrested the other man, Babkhel said.

The army launched the offensive in the South Waziristan region on the Afghan border on October 17.

Soldiers have retaken control of Kotkai, a strategic town and the birthplace of Pakistani Taliban chief Hakimullah Mehsud, the army said on Saturday.

About 150,000 people have fled their homes in South Waziristan but aid officials do not expect the exodus to become a humanitarian crisis, as did a similar offensive in the Swat valley this year.

Also on Saturday, a military transport helicopter crashed in the Bajaur region, northeast of Waziristan, where soldiers are also fighting militants. Four crew members were killed, military officials said.

(Reporting by Kamran Haider; Editing by Robert Birsel and Paul Tait)