KABUL, June 18 (Xinhua) -- Four police were killed and three others were injured as a roadside bomb struck a van of border police force in Afghanistan's eastern Khost province Wednesday, an official said.

    A bomb planted by militants hit a vehicle of police in Ali Shir district at 11:00 a.m. local time, killing four policemen on the spot and wounding three others, an official of the Border Police Force in the area, Colonel Shir Ahmad, told Xinhua.

    He blamed the Taliban insurgents for the incident, saying Taliban rebels by conducting such attacks want to destabilize security in the province.

    The past three weeks saw intensified militants' attacks, the fiercest of this year in the country, where last year insurgency-related valence claimed 8,000 people's lives, a record high since hard-line Taliban regime collapse in 2001.