Gunmen shot dead a female aid worker in Somalia's capital on Tuesday, police said, in the latest of several targeted attacks against humanitarians in the long-chaotic Horn of Africa nation.

Maryan Abdullahi, a Somali employee with the World Health Organization, was killed in Mogadishu's Bakara market when two men with pistols approached and fired at close range, police Capt. Mohamed Hussein said.

The attackers fled the crowded, open-air market that has seen similar ambushes by suspected extremists in recent years, Hussein said.

WHO officials did not immediately comment.

No group immediately claimed responsibility for the killing, which has sent shockwaves through Somalia's aid community.

Somalia is one of the world's most dangerous places for aid workers. Many have died in bombings by al-Qaida-linked al-Shabab extremists, who continue to control large parts of rural Somalia and often attack the capital.

At least 30 aid workers were killed in 2016 and 2017, the United Nations has reported. Violent incidents against aid workers went up sharply last year, including the abductions of more than 30 humanitarian staffers, in part because of scaled-up relief operations during a severe drought.