Hundreds, possibly thousands, of civilians in two central Somali regions have reportedly fled their homes in fear, after an ambush Monday on Ethiopian troops triggered a fierce gun battle with Islamist fighters.  VOA correspondent Alisha Ryu reports from our East Africa Bureau in Nairobi.  

It is not yet known how many people have fled villages in the Hiran and neighboring Galgadud regions, but residents describe it as a chaotic mass exodus, reminiscent of people fleeing similar fighting in the war-torn capital, Mogadishu.

Eyewitnesses tell VOA that numerous civilians, terrified of being caught in the crossfire of the fighting between Ethiopian troops and Islamist fighters, left the villages of Mataban and neighboring Guri'eel. 

The fighting between the Ethiopian army and Islamist-led insurgents in Mogadishu began 10 months ago, shortly after the Islamic Courts Union lost power to Somalia's secular interim government in an Ethiopia-led military campaign.  The violence has displaced more than one million people, prompting the United Nations to call the situation the worst humanitarian crisis in Africa.  

The former governor of Hiran, Yusuf Hussein Iyu, tells VOA that the crisis in his region began Monday in an area near Mataban, when a roadside bomb exploded close to an Ethiopian military convoy traveling through the area.  

Ethiopian soldiers opened fire, sparking a gun battle with Islamist insurgents.  Two Ethiopian soldiers, as well as two civilians, were reportedly killed.  

The former governor says some civilians were killed and wounded during the battle, triggering a panic in Mataban village.  Iyu says he has heard that insurgents have moved out of the area and are mixing with fleeing civilians.

VOA has learned that the insurgents who launched the attack Monday on the Ethiopian convoy are most likely fighters loyal to Adan Hashi Ayro, an al-Qaida-trained militant who founded a radical youth group called the Shabbab three years ago in Mogadishu.

The villages of Mataban and Guri'eel are home to many people of the Ayr clan, a sub sub-clan of the Hawiye, the most dominant clan in the capital.   Ayro, who is an Ayr, is believed to have moved his fighters from Mogadishu to Mataban and Guri'eel in recent days, possibly in an attempt to regroup and gather new recruits.  

Some reports from Mogadishu say Ayro caused a deep split within the Shabbab leadership in Mogadishu earlier this month, when he called for a holy war against African Union peacekeepers over the objection of his senior commanders.

But some Somalis speculate that the Shabbab has not split, but is simply changing tactics.   Under pressure from the Ethiopians in the capital, they say the Shabbab may have decided to spread out to make their guerrilla war far more difficult to contain.