Assailants threw a homemade bomb at a U.N. convoy in which the world body's top diplomat in the country was traveling in Libya's main eastern city on Tuesday, according to a security official.
The official, Basit Haroun, said that neither Ian Martin, the U.N. envoy, nor any of his traveling companions were harmed in the attack in Benghazi. Authorities launched a search for the attackers, he said.
U.N. deputy spokesman Eduardo del Buey said in New York that "while on a visit to Benghazi, the head of the U.N. support mission in Libya had what appeared to be an explosive device thrown at his convoy."
"No one has been hurt and the authorities are investigating," del Buey said.
Libya has been hit by lawlessness since the ouster last year of Moammar Gadhafi, with militiamen who fought the dictator's forces refusing to stand down or hand over their weapons.
Martin was in Benghazi to address students and staff of the city's main university.
Benghazi is the birthplace of the uprising that toppled Gadhafi's 41-year regime.