Somali troops shot and killed seven civilians in southern Mogadishu after accusing them of being Islamic insurgents who have recently launched a series of hit-and-run raids on government targets, witnesses said Friday.

In a separate incident on Thursday, three gunmen shot a Somali aid worker affiliated to the U.N. World Food Program, a witness said, the latest in a string of attacks on humanitarian workers.

Witness Liban Ahmed said government soldiers killed at least seven civilians and wounded four during an operation in Daynile neighborhood in the capital.

Government commander insisted the dead were Islamist fighters and had been shot just before they attacked government troops. But Asha Sheikh, another resident, said "there was confrontation apart from the troops shooting at civilians."

Islamist fighters have briefly captured over a dozen strategic towns in the last few months and on Thursday attacked a military base near the seat of the country's Parliament.

In a separate attack, witness Abdirahman Munim said three gunmen shot the deputy chairman of a local aid organization at a food distribution point 13 kilometers (8 miles) outside the capital. Ali Bashi Alore is the deputy chairman of local aid organization SORDA, which helped the U.N. distribute food.

"Three men armed with pistols come to him and disputed with him for about five minutes and then shot him twice in the head," said Munim.

Munim said he believed Alore had been killed in the attack, but Peter Smerdon, a Nairobi-based spokesman for the WFP, said initial reports reaching the organization indicated Alore had survived and been hospitalized.

It was the third shooting of a worker connected with the U.N. this week. On Sunday, attackers shot dead the head of the U.N. Development Program for Somalia, and on Monday a truck driver in a convoy of food was fatally shot at a checkpoint.

Aid workers say Somalia is in the grip of a humanitarian emergency, with more than 2 million people dependent on aid. Efforts to help are hampered by fierce fighting between Islamic insurgents and government troops, who are supported by Ethiopian soldiers.

The Islamists vowed to fight an Iraq-style insurgency after the Ethiopians drove them from power a year and a half ago at the request of the shaky U.N.-supported transitional government. But the administration has failed to deliver any basic services, is riddled with corruption and comes under daily attack from the insurgents.

Arid impoverished Somalia has not had a functioning government since warlords overthrew a socialist dictator in 1991 then turned their clan-based militias on each other.