The U.S.-based group Human Rights Watch has released a detailed report on the fighting that devastated the Somali capital, Mogadishu, in March and April of this year. The report concludes that Ethiopian, Somali, and insurgent forces are responsible for serious violations of the laws of war, which have caused massive civilian casualties and suffering. VOA Correspondent Alisha Ryu has the story from our East Africa Bureau in Nairobi.

Human Rights Watch says its 113-page report is the result of six weeks of research and interviews with more than 100 people, who lived through two months of the worst fighting in Somalia in recent memory.

As many as 3,000 civilians were killed and 400,000 others displaced during fierce street battles between mostly Islamist insurgents trying to topple the country's secular interim government, and Ethiopian and Somali troops protecting the fragile administration.

Speaking to reporters in Nairobi, the director of the group's London office, Tom Porteous, said all sides in the Somali conflict violated the international law that requires warring parties to avoid harming civilians.

"The main violations we documented on the part of the insurgents were indiscriminate bombardment, mostly of mortar rounds, into heavily populated civilian areas," he said. "Secondly, there was the deployment of insurgent forces in civilian areas. On the side of the Ethiopians, our report documents very heavy, indiscriminate bombardment of civilian areas and that included what is known as area bombardment, where the Ethiopian forces would set their coordinates at a certain level and then carry out the bombardment. Then, they would set it at another level and they would basically go up a grid, covering a whole area. That is a fundamentally inappropriate means of warfare in a heavily populated civilian area and it amounts to a war crime."

Human Rights Watch says Somali government troops played a secondary role to the Ethiopian military in the battles. Nevertheless, the group says Somali soldiers are also guilty of wrongdoing, including failing to warn civilians about potential fighting, looting personal property, impeding relief efforts for displaced people, and mistreating detainees.

The watchdog also criticized two of the largest donors and key players in the region, the United States and the European Union, for not doing enough to stop the abuses.

"One of the depressing features about the conflict in Somalia over the last year is that, in spite of quite well-reported abuses that have been taking place, there has been very little condemnation," Porteous said.

The Somali capital has had little peace since late December, when Ethiopia-led forces drove Islamists out of power and installed the internationally recognized-but-unpopular transitional government in Mogadishu.

Even though large-scale fighting has not erupted since April, the United Nations says near-daily violence in the city has prevented the vast majority of residents from returning to Mogadishu. Continuing violence has caused thousands of others to leave the city in recent weeks, some for the second time.

Many fleeing Mogadishu now are from neighborhoods close to the site of a government-hosted national reconciliation conference being boycotted by Islamists leaders. The building has been the target of numerous attacks since the conference opened in mid-July.

The launch of the report has been timed to coincide with the start of the U.N. Security Council deliberations on whether to turn the current African Union peacekeeping force in Somalia into a U.N. force. Tom Porteous says his group is calling for the U.N. Security Council to include a strong civilian protection mandate in any future peacekeeping mission in Somalia.