Somalia ? Hundreds of foreigners fighting alongside Somali Islamic insurgents have driven this week’s fierce battles against government forces, which have killed more than 100 people, the U.N. envoy to Somalia said Friday.

Concern that the government might fall is mounting. Observers fear that if the al-Qaida linked insurgents seize the capital, they will gain a safe haven on the Horn of Africa.

The U.N. Security Council on Friday condemned the upsurge in fighting and gave strong support to the country’s leaders. A statement approved by all 15 council members demanded that opposition groups immediately end their offensive, renounce violence and join reconciliation efforts.

Somalia’s coastline borders an important sea trade route and the Horn juts into the Indian Ocean just below the oil-rich Arabian peninsula.

The government controls only one major road in the capital, Mogadishu, along with some government installations, with the assistance of about 4,350 African Union troops.