Abdenasir Aden Muse, head of the World Food Program's aid monitors in Marka, the provincial capital of the Lower Shabelle region, was shot dead as he left a mosque after evening prayers.
"Two men armed with pistols stopped him before shooting him a number of times," an eyewitness who requested anonymity for fear of reprisals, told Xinhua by phone. "They fled away from the scene after they fired the shots."
Muse was rushed to the main hospital in the town but pronounced dead on arrival. Hundreds of local residents went to the hospital to express their solidarity with the victims' family and friends in Marka, 100 km south of the capital, Mogadishu.
On Wednesday, Hassan Mustafa, the Somalia head of an Italian NGO operating in Marka, escaped an abduction attempt but his driver was killed after gunmen opened fire on his vehicle as he headed to his office in the town where a number of local and international NGOs operate.
Also early this month, Saverio Bertolino, a senior UN foreign aid worker, was wounded and his driver killed in a roadside bomb explosion that hit their vehicle in the southern town.
The series of attacks on aid agencies and humanitarian workers comes after the Islamist Al-shabaab group early in the month banned two international aid agencies from operating in areas they control in South Somalia after they accused them of "anti-Islamic activities". The group also issued warning to other agencies.