Heavy fighting between Ethiopian troops and insurgents erupted again late Tuesday in the Somali capital, Mogadishu, killing and wounding nearly two dozen people. As VOA Correspondent Alisha Ryu reports from our East Africa Bureau in Nairobi, there are indications that the latest attacks against the Ethiopians may have been carried out largely by members of a radical Somali youth group, trained in guerrilla warfare.

Residents of Mogadishu describe the firefight Tuesday as being as intense as the clashes that took place between March 29 and April 1, which killed as many as one thousand people and prompted hundreds of thousands of others to flee the city.

The latest violence, which erupted around 8:30 in the evening and lasted several hours, targeted Ethiopian troops protecting the presidential palace.

Insurgents fired mortars at the troops, who responded with artillery and tank fire. The shelling cut off electricity in some neighborhoods in the capital, causing havoc in the streets as people tried to flee their homes in darkness.

After the clash, leaders of the city's dominant Hawiye clan denied that the fighting had broken a fragile truce, reached between the clan and the Ethiopian military nearly two weeks ago.

On Wednesday, a senior Hawiye elder Abdullahi Sheik Hassan acknowledged that militiamen in his clan still engage in sporadic gunfights with Somali government forces. But he says clan militiamen were not involved in Tuesday's attack against Ethiopian troops. "The ceasefire is still on. There is no fighting here. There is no problem," he said.

Mogadishu's increasingly violent insurgency began in early February, a month after Ethiopian-led forces drove out Somalia's Islamists from the capital and ended their six month long rule over much of southern and central Somalia.

The insurgents are drawn mostly from radical Islamists and their supporters and Hawiye clansmen, angry over perceived efforts by the Somali transitional government to weaken and marginalize the tribe.

The two groups are believed to have cooperated in some of the previous attacks against Ethiopian and Somali forces in Mogadishu.

But Tuesday's attack was unusual in that the assault took place at night.

Several U.S. military veterans, who fought against Somali militiamen in Mogadishu in the early 1990s, tell VOA that Somalis hardly ever engaged U.S. troops at night, preferring to fight during the day when they could see.

Analysts say Tuesday's assault may have been the work of a Somali radical youth group called the Shabbab, whose founder is reportedly the new head of al-Qaida's cell in Somalia.

Adan Hashi Ayro was trained by al-Qaida in Afghanistan and some of his followers in the Shabbab have told VOA that they received extensive guerrilla warfare and terrorist training while the Islamists were in power last year.

Islamist leaders have repeatedly denied that their movement has any ties with terrorist groups. They blame Washington for the violence in Somalia, saying it encouraged Ethiopia to get involved in what they say are Somalia's internal problems.