KABUL, Afghanistan — A bombing in western Afghanistan on Tuesday killed four Afghan policemen, including a local police chief.

The bomb appeared to be targeting the top police official in Obe district and exploded as his vehicle drove past, said Naqib Arwen, a spokesman for the governor of Herat province where the blast took place.

"It was a very strong explosion," he said. "We are investigating, but our initial reports show that it was a remote-controlled bomb."

In eastern Afghanistan's Logar province, a senior Taliban leader who is believed to have played a role in the kidnapping and subsequent murder of two U.S. sailors in July, was captured along with two of his associates on Monday, according to NATO.

NATO said the leader was also responsible for attacks against Shank military base and bombings in the Baraki Barak district of Logar province.

Petty Officer 3rd Class Jarod Newlove and Petty Officer 2nd Class Justin McNeley were driving through a dangerous part of eastern Afghanistan when they became involved in a fire fight on July 23. The bodies of both men were eventually recovered.

NATO also said one of its air strikes on Monday killed a senior leader of the Islamic Movement of Uzbekistan, who was serving as a Taliban chief in the northern Takhar province where violence is on the rise.

The air strike killed Qari Mahmad Umar, a bomb expert and trainer responsible for planting bombs in Takhar and Kunduz provinces.