Sudanese security forces arrested two suspects in the murder of a U.S. diplomat Saturday, the official state news agency announced.

John Granville, an official for the U.S. Agency for International Development, was being driven home late at night on Jan. 1 when another vehicle cut off his car and opened fire, killing both the diplomat and his driver, before fleeing the scene.

Acting on a tip Saturday, the police closed in on the suspects in a suburb of Khartoum's twin city, Omdurman, SUNA quoted a police statement as saying. They were arrested after an exchange of fire.

Several people were injured, including police and bystanders, according to the statement.

U.S. Embassy spokesman Joel Maybury said that the embassy was aware of the arrests but had no further comment.

Following the January shooting, a team of FBI agents was sent to Khartoum to work with Sudanese authorities on the investigation.

Sudanese officials have insisted the assassination was not a terrorist attack, though a previously unknown group called Ansar al-Tawhid took responsibility for the killing in an Internet chat room on a militant Web site. The claim could not be verified.

USAID said Granville was working to implement a 2005 peace agreement between Sudan's north and south that ended more than two decades of civil war, separate from the conflict in Darfur.

Granville's killing was the first assassination of a U.S. diplomat in Sudan since 1973.