Reconciliation talks in Khartoum between Somalia's transitional government and Islamists who control much of the country have ended before the rival parties even met face-to-face.
On Wednesday, the Somali talks deteriorated into a round of accusations and insults.
The Somali government delegation accused Islamists of attempting to murder Somalia's president, and forming hit squads to assassinate other Somali leaders.
Islamists dismissed the charges, calling them absurd.
At day's end, diplomatic mediators were exhausted and frustrated by the lack of progress.
Rina Kristmoen of the Norwegian Embassy in Kenya said the talks were a disappointment to the international community.
"We hope they will commit themselves to meet again," he said. "They know the situation on the ground is critical. It was important for them to meet now in order to reduce tension and to be able to continue this dialogue is so important. It is very unfortunate that they did not agree to meet."
Following their arrival in Khartoum on Monday, the Islamist delegation said they would not meet with government representatives until Ethiopian troops leave Somalia.
Ethiopia's presence in the embattled nation has long been a source of tension.
Islamists accuse Ethiopia of sending troops into Somalia to bolster the struggling government army.
The Somali government admits a few Ethiopian soldiers have entered the nation, but characterizes them as military trainers, rather than fighters.
Islamist leaders on Wednesday defended themselves against accusations that they are not the legitimate leaders of Somalia, despite controlling much of the country.
Head of the Islamist delegation, Ibrahim Hassan Addou, told reporters that the Islamic courts have popular support.
"Our record speaks for itself," he said. "We have created the stability and peace that the entire world could not do. Now the Somali people know the value of the Islamic courts and the quality of the leadership of the Islamic courts. We don't want to spend time on cheap propaganda."
Observers now worry that war in Somalia appears imminent.
Eritrean and Ethiopian forces are both present in the nation. Observers fear the start of a proxy war between the long-time rivals, with Somalia as the battleground.
The Islamic Courts seized much of southern Somalia, including the capital, Mogadishu, in June.
The nation has been without a functioning government since 1991, when warlords toppled dictator, Mohammed Siad Barre.