CAIRO — The United States has begun a review of embassy security in Sudan in wake of the killing of a U.S. official in Khartoum on Jan. 1.

The official, driven home from a New Year's party, was ambushed and killed in an attack believed to have been conducted by Al Qaida. The Sudanese driver was also shot dead, Middle East Newsline reported.

The State Department has sent a team to investigate security for U.S. diplomats in Khartoum. The delegation was led by U.S. Principal Deputy Assistant Secretary of State for African Affairs Linda Thomas-Greenfield and U.S. Foreign Service director-general Harry Thomas.

"They are here to talk about security relating to the embassy after what happened," U.S. embassy spokesman Walter Braunohler said.

An Al Qaida-aligned website said Ansar Al Tawhid in Sudan claimed responsibility for the killings. This was the first such claim issued by the group.

Sudan has also been investigating the killing of John Granville, who worked for the U.S. Agency for International Development. No suspects have been prosecuted, although a witness was found.

Sudanese Justice Minister Mohammed Ali Al Mardi said the unidentified witness was questioned by police. Sudanese newspapers said police have drawn a sketch of the suspect. The Sudanese daily Al Sahafa suggested that Granville's vehicle was shot from a rooftop.