Geneva - The United Nations' refugee agency on Tuesday warned of "widespread rape" and a rise in prostitution in Somalia as the Horn of Africa country sinks deeper into chaos.

United Nations High Commissioner for Refugees (UNHCR) spokesman in Geneva, William Spindler, said "serious atrocities" were being carried out by parties to the conflict.

Thousands have been forced to flee their homes in "some of the heaviest and bloodiest street battles" in the capital Mogadishu since the latest outbreak of government forces and opposition Islamist groups in early May, he said.

"Women are selling their bodies to get out of Mogadishu," Roberta Russo of the UNHCR's Somalia team told the German Press Agency dpa in a telephone interview from Kenya.

Testimonies collected by the agency indicate that many people are unable to flee, as they cannot afford the bus fair out of the capital.

Russo noted the case of one woman, aged 23, who said she had become a prostitute to gather enough money to reach the coast. There, she would continue to charge for sex, in order to later pay to be smuggled Yemen.

"This is not an isolated case," said Russo.

Earlier this year, Shamsul Bari, the UN's expert on Somalia said its inhabitants "suffer one of the most precarious existences I have witnessed."

The UNHCR said it was "gravely concerned about the violence and the fact that it is further aggravating an already desperate humanitarian situation."

Last week, the agency said nearly 100,000 people had fled the war-torn capital.

"There is clearly very little regard for the safety of civilians in Somalia," said Spindler. He noted hostage takings and the shelling of civilians areas.

"The situation is getting worse and worse," he added, noting that aid agencies were having more trouble gaining access to civilians than in the past.

Some 36,000 people are estimated to be trapped in areas of heavy fighting in Mogadishu. Reports indicate that people remain for days without food or water, as the conflict continues around them, according to the UNHCR.

The International Committee of the Red Cross said last month it saw "sharp deterioration" in the humanitarian situation in Somalia, which has been fraught with conflict since the early 1990s.(dpa)