A conference aimed at bringing peace to Somalia opened briefly Sunday, but was immediately adjourned after some delegates did not arrive and mortars exploded near the venue.
Organizers say they are postponing the meeting until Thursday to give delegates more time to arrive in the capital, Mogadishu.
Somalia's interim president, Abdullahi Yusuf, was addressing several hundred delegates at the conference when mortar shells exploded nearby. He urged them not to be afraid and said the conference will continue.
Police say three people were injured in the explosions.
On Saturday, Islamic insurgents threatened to kill anyone who attends the conference.
The country's Islamist movement, the Islamic Courts Union, is boycotting the meeting to protest the presence of Ethiopian troops in the country.
The Ethiopians helped the government push the Islamists from power in Mogadishu and other Somali cities late last year. Mogadishu has since suffered months of chronic violence, with roadside blasts, suicide bombings and killings becoming an almost daily occurrence.
The peace conference has been delayed several times because of security concerns and organizational problems.
More than 1,000 delegates, drawn from the country's fragmented clans, have been invited to the reconciliation talks. President Yusuf has vowed that no amount of violence will derail the conference.