Mogadishu, Somalia ? Somalia government soldiers, joined by troops from neighboring Ethiopia, advanced toward Somalia’s capital Tuesday as Islamic fighters dug in and promised a “new phase” in the war – a chilling pronouncement from a movement that has threatened suicide attacks.

Somalia called on the Council of Islamic Courts militias, bloodied by a week of artillery and mortar attacks, to surrender and promised amnesty if they lay down their weapons, government spokesman Abdirahman Dinari said.

A U.N. official, meanwhile, said Tuesday that Ethiopian-backed government troops were advancing on Mogadishu, the capital, from two directions and facing stiff resistance.

Francois Lonseny Fall, the top U.N. envoy to Somalia, also said 35,000 Somalis had crossed into neighboring Kenya to escape the fighting, which forced the U.N. to suspend aid delivery to two million Somalis.

As many as 1,000 people may have been killed and 3,000 wounded in the fighting, many of them foreign radicals, Ethiopian Prime Minister Meles Zenawi said.

Meles said about 3,000 to 4,000 Ethiopian forces, which entered Somalia on Saturday, may soon wrap up their offensive against the Islamic militias that until recent days controlled most of southern part of the country.

“As soon as we have accomplished our mission – and about half of our mission is done, and the rest shouldn’t take long – we’ll be out,” Meles told reporters in the Ethiopian capital, Addis Ababa.

The U.N. envoy, Fall, called the fighting “disastrous” for the Somalian people and asked the Security Council to call for an immediate cease-fire.

The council took no immediate action on a draft presidential statement circulated by Qatar calling for a cease-fire and withdrawal of foreign forces, specifying Ethiopian troops.