The Islamists launched an insurgency that has killed thousands of civilians and prompted Somalia's president to resign in December, saying he had lost control of the country.

The lawlessness in Somalia also has allowed piracy to flourish off its coast. Last year, pirates seeking multimillion-dollar ransoms attacked 111 ships in the Gulf of Aden and seized 42 of them.

The Ethiopians announced late last year they would end their unpopular presence as demanded under an October power-sharing deal signed between the Somali government and a relatively moderate faction of the Islamists.

Al-Shabab, is not part of the agreement and has made dramatic territorial gains in recent months. The U.S. State Department considers it a terrorist organization with links to al-Qaida — a claim al-Shabab denies.

Despite Hussein's plea for peace, al-Shabab has said in recent days that Ethiopia's withdrawal would not stop it from fighting because the group's goal is to establish an Islamic state in Somalia.

The Ethiopian army, one of Africa's largest, was viewed by many Somalis as abusive and heavy-handed. Ethiopia long said it wanted to pull out after stabilizing Somalia, but opponents said Ethiopia — a mainly Orthodox Christian country — was interested in preventing an Islamist regime in neighboring Somalia.

The two countries have been rivals for decades, and fought in the late 1970s over a southeastern region of Ethiopia populated principally by people of Somali origin.

Fadumo Wehliye, who lost three of her eight children during the violence, described the Ethiopian pullout as "great" and said she now would go back to home in Mogadishu.

"For the last two years ... I have been living in a makeshift house in the outskirts of the capital," she said. Now "I will return to my home."

The Islamist groups, once unified, have split since gaining more territory last year. They have begun fighting one another for control of several towns, with the government-allied Islamists claiming to be in charge of some of them.

Last year, Somalia's transitional government agreed to share power with a faction of the Alliance for the Re-Liberation of Somalia, a relatively moderate group that split from al-Shabab.

Hussein Siyad Qorgab, deputy chairman of the alliance faction, urged all to "come together and make a unity government."

The U.N. envoy to Somalia praised the Ethiopians for honoring of a withdrawal commitment made with the power-sharing deal signed last year in Djibouti.

"The ball is now in the court of the Somalis, particularly those who said they were only fighting against the Ethiopian forces, to stop the senseless killings and violence," Ahmedou Ould-Abdallah said in a statement issued Tuesday in neighboring Kenya.