KABUL (AFP) -- A suicide bomber detonated a taxi filled with explosives near the Afghan Parliament in the capital Kabul Friday, killing four people including a policeman and wounding four others, police said.

The attack was the third suicide blast in the heavily-secured city this year amid a raging insurgency by the Taleban militia, which was ousted by U.S.-led forces in late 2001.

The bomber struck a few hundred meters (yards) from the Parliament building, killing three civilians and one policeman, Kabul criminal investigation police chief General Alishah Paktiawal told AFP.

"It was a suicide bombing. Four people were killed and four others were injured. The bomber was driving a yellow and white taxi," Paktiawal said.

Paktiawal said it was unclear if the bomber was targeting the Parliament building. "An investigation is under way," he said.

Iraq-style suicide attacks are common in southern Afghanistan where the Taleban-led insurgency is at its strongest, but they have previously been rare in Kabul.

Four civilians were killed and another 12 wounded when a suicide bomber targeted an intelligence director's vehicle in Kabul on March 28. The intelligence official survived.

About a week earlier a suicide attacker rammed an explosives-filled car into a U.S. embassy convoy in the capital, wounding five embassy staff and guards and at least three passers-by.

The Taleban has vowed a wave of such blasts this year after nearly 140 last year across the country killed about 200 civilians and scores of Afghan and foreign security officials.

In the deadliest attack in Afghanistan this year, more than 20 people including two Americans and a South Korean soldier were killed on February 27 in an attack on the main U.S. base at Bagram, about 60 kilometers (40 miles) from Kabul, while U.S. Vice President Dick Cheney was visiting.