Sheikh Dahir Aweys, a senior leader of the Islamic courts, said: "The Somalis are now more united than before proving that they are one nation against the Ethiopian invaders."
In a phone call with Al Jazeera on Saturday, Aweys offered to negotiate with the Somali government if its Ethiopian allies leave the country.
A conference on peace and reconciliation that was originally to be held this month, but had been postponed to May because of continuing violence, is now scheduled for June 14.
Ali Mahdi Mohmamed, the chairman of a committee planning the conference, on Sunday, said: "We are trying to reconcile the Somali clans and we are waiting for international support."
"The situation is Somalia has gone from bad to worse after the intervention of Ethiopian troops"
Abed, Kumasi, Ghana
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Four days of bloodshed that started in late March killed hundreds of people - and possibly more than 1,000 - in the worst fighting in 15 years.
The battles started when Ethiopian troops used tanks and attack helicopters in an offensive to crush fighters tied to the Islamic courts.
The Islamic courts movement was driven from power in December by Somali and Ethiopian soldiers, accompanied by US special forces. The US has accused the courts of having ties to al-Qaeda.
Aweys, on Saturday, said the US was taking revenge against Somalis because of the death of US troops in Somalia in the 1990s.
He denied any links between the Islamic courts and al-Qaeda, saying no foreign fighters were available on Somali territories.
The UN refugee agency says more than 200,000 people have fled Mogadishu since the beginning of February. The agency had earlier said 124,000 people fled - highlighting the difficulty of getting accurate figures from a country with no effective central government or institutions.