By Stephanie Nebehay

GENEVA (AlertNet) - Canada has extended its vital naval escorts of U.N. food shipments in Somalia's pirate-infested waters until Oct. 23, the World Food Programme said on Friday.

The United Nations food agency welcomed the four-week extension, which will allow it to continue delivering emergency rations to about 2.4 million people in the war-torn country.

"It is a great relief to us," WFP spokeswoman Emilia Casella told a news briefing in Geneva. "We continue to look for naval escorts beyond October 23."

Canada, whose frigate Ville de Quebec has provided escorts since mid-August, had been due to halt its service on Saturday. France, Denmark and the Netherlands supplied escorts previously this year.

Heavily armed Somali gunmen have seized more than 30 vessels this year, making the waters off the Horn of Africa the most dangerous in the world and hampering aid shipments. Three WFP ships were hijacked in the Gulf of Aden last year.

The agency is trying to provide 35,000 tonnes of food to Somalia each month, 90 percent of it by sea from ports in Kenya and South Africa, according to Casella.

"Patrols are not enough to deter pirates," she said. "We need escorts."

Aid agencies voiced concern on Friday at a fresh exodus from Mogadishu due to intensified fighting between Islamist insurgents and Somalia's transitional government and its Ethiopian military backers.

At least 15,000 people fled their homes in the capital this week, the U.N. High Commissioner for Refugees (UNHCR) said.

"Many have no idea where to find shelter as they try to escape massive and indiscriminate shelling and violence that has killed some 200 people and wounded scores of civilians, including women and children," spokesman Ron Redmond said.

The UNHCR feared that the exodus from Mogadishu would rise with the end of the Muslim holy month of Ramadan next week.

Desperate Somalis continue to stream over the porous but officially closed border into Kenya at a rate of about 5,000 refugees each month, Redmond said.

The population at Dadaab refugee camp in Kenya, some 80 km (50 miles) from the border with Somalia, has swollen to more than 215,000, more than twice its intended population, he said.