JOHANNESBURG — The Red Cross says it is shocked by the killing of one of its staffers in South Sudan as dangers to humanitarian workers rise amid the country’s civil war.

A statement Saturday by the International Committee of the Red Cross said driver Lukudu Kennedy Laki Emmanuel was shot and killed Friday by unknown attackers after delivering aid in Western Equatoria.

The Red Cross convoy had been clearly marked and all parties in the conflict had been notified of the organization’s presence, the statement said.

South Sudan has become one of the world’s most dangerous places for aid workers, and a new United Nations report says the situation is worsening. That complicates efforts to reach the estimated 6 million South Sudanese, or roughly half the population, said to be severely food insecure.

At least 84 aid workers have been killed since 2013, including at least 17 this year, the U.N. humanitarian agency says. Most have been local workers.

Hundreds of incidents of aid restrictions have been reported since January, including attacks on humanitarian compounds and the looting of supplies and convoys, a new report by the U.N. agency said Friday. About 300 aid workers have been relocated since January because of security issues.

Both the government and rebel sides in South Sudan’s civil war have been accused of restricting aid access. The conflict that began in December 2013 has killed tens of thousands and sent about 2 million people fleeing the country.