U.N. Secretary-General Ban Ki-moon has expressed grave concern at the violence in Somalia. VOA's Peter Heinlein at U.N. headquarters reports officials also fear the consequences of Somalia's burgeoning humanitarian crisis.

On a day when Somalia's prime minister claimed strong gains over Islamic insurgents, Secretary-General Ban expressed doubts about the Mogadishu government's ability to maintain order in the war-ravaged country. He told reporters he had held extensive talks on Somalia during his just-completed trip to the Middle East.

"I am gravely concerned about the on-going violence in Somalia and I have discussed with all parties concerned, while traveling with the Secretary-General of the League of Arab States and other leaders," said Ban Ki-moon. "I am also very much troubled by the fact that the Transitional Federal Government is not able to sustain the momentum thus created politically."

The top U.N. humanitarian official this week described Somalia as the most dangerous place in the world for relief workers to operate. Undersecretary General John Holmes said humanitarian aid operations were being hampered by probably the worst fighting in and around Mogadishu in 16 years.

"The U.N. had been helping something like a million people already, and that situation had seemed to be improving, which makes it particularly tragic the deterioration we've seen in recent weeks and recent days," said John Holmes. "The level of displacement from Mogadishu has reached something like 320,000 , which is one-third of the entire population of the city, and that figure is rising every day as the fighting continues."

Holmes said aid is reaching only about 60,000 of the 320,000 homeless. He described their condition as 'worrying'.

"They have virtually nothing, and a lot of them are living under trees, which they are apparently having to rent, for shelter, and they are in great difficulty," he said.

Holmes says civilians are being caught in the crossfire as Ethiopian and Somali force battle insurgents in the streets of Mogadishu. He accused all sides in the fighting of responsibility for failing to stay within international law. He said one hospital had apparently been deliberately targeted by shelling and artillery fire.

Somalia has not had an effective government since 1991. Ethiopian troops entered the country late last year to help the transitional government drive out rival Islamist forces who had control of Mogadishu. Islamist fighters are believed to make up the majority of the insurgents.