Hospital workers and residents in the Somali capital Mogadishu say more than 40 people have been killed and more than 100 wounded since late Thursday in battles between Ethiopian troops and Islamist-led insurgents. As VOA Correspondent Alisha Ryu reports from our East Africa Bureau in Nairobi, the escalation in violence follows a recent Ethiopian troop build-up in the capital.

A hospital worker in Mogadishu, who did not want to be identified, tells VOA that the latest round of fighting is the worst he has seen in months.

He says it began late Thursday after Ethiopian troops launched a house-to-house search and fired tank shells on suspected insurgent hideouts in southern districts of the city.

"The Ethiopians carried out a massive operation in some areas and then big fighting took place. The Ethiopian military was using tanks. Almost 50 people were killed in Mogadishu in the past 24 hours, including seven Ethiopians. There are still dead bodies out in the streets," he said.

Last week, the government in Addis Ababa deployed as many as two-thousand extra troops in Mogadishu. The exact number of Ethiopian troops in the capital is not known, but it is estimated to be in the tens of thousands.

In an interview with VOA on Monday, the spokesman for Ethiopia's Ministry of Foreign Affairs, Wahide Belay, confirmed that Ethiopia was prepared to launch a renewed military offensive against insurgents, who have fought a relentless guerrilla war against Ethiopian troops and Somalia's Ethiopian-backed interim government in Mogadishu for nearly a year.

Addis Ababa says the insurgency is not a popular uprising, but is being carried out by a small group of extremists, loyalists, and sympathizers of the Islamic Courts Union. The Islamist movement ruled most of southern and central Somalia for six months before an Ethiopian-led military campaign last December ousted the Islamists from power.

Mogadishu residents say for the first several months, the insurgency was not a popular uprising. Several hundred Islamists formed the core of the insurgency, including al-Qaida-trained militants opposed to Ethiopia, the United States and the secular interim government they support.

But public anger toward the Ethiopian presence in Somalia is said to be growing, stemming from allegations that Ethiopian troops are committing human rights violations, including murder and rape, against Somali civilians.

The hospital worker in Mogadishu says a few days ago, he heard angry residents vowing to take revenge against Ethiopian troops, who they say were firing on innocent people.

"They say that Ethiopians kill any man or young man they see, thinking that he is part of the fighting."

Such allegations have surfaced before, and Addis Ababa has vehemently denied that its troops are committing atrocities.

The Ethiopian army first tried to crush the insurgency in March and April of this year, triggering weeks of fighting that left hundreds dead, a large section of the capital destroyed, and prompted 400,000 civilians to flee.

Human rights groups condemned both Ethiopia and the insurgents for firing indiscriminately and endangering civilians.