Gunmen killed a Swiss national working in Libya for the International Committee for the Red Cross when they intercepted his car in the city of Sirte on Wednesday, the Red Crescent said.
"The ICRC's head of mission in Misrata was killed today as he was carrying out a visit to Sirte," Red Crescent spokesman Mohamed Mustafa al-Misrati told AFP.
Misrati said the ICRC worker was killed when unidentified gunmen stopped his car in the coastal city of Sirte, 500 kilometres (300 miles) east of Tripoli, where he had been working with the Libyan Red Crescent's local branch.
The ICRC in Geneva confirmed the death an employee in Libya.
"He was attacked by gunmen as he left a meeting with two colleagues. He died in Sirte's hospital. His colleagues are unhurt but in shock," ICRC spokesman Wolde Saugeron told AFP.
Signup to our newsletter and follow us on Facebook and Twitter!
Since the popular uprising that toppled dictator Moamer Kadhafi in 2011, the country has been awash with heavy weapons and rival militias with varying ideological and political bents have controlled tracts of territory across the North African nation.
Attacks have targeted members of the security forces and foreigners in eastern Libya, particularly the city of Benghazi, where several powerful Islamist militias are based.
No group has claimed the attacks, but jihadist groups in the region have been blamed for the bombings and shootings.
Red Cross offices in Benghazi and Misrata were targeted in 2012, although they left no casualties.