A key al-Shabab leader in Somalia, Sheikh Hassan Dahir Aweys, has so far refused to surrender, elders from his clan have told the BBC Somali Service.
The UN has reported that Mr Aweys has handed himself over to a pro-government administration in central Somalia after falling out with al-Shabab's leader.
But Mr Aweys is in Galmudug region with his militia with the consent of the local authorities, the elders say.
They had flown there from the capital to see if he was willing to make peace.
Mr Aweys is seen as the elder statesman of Somali Islamists and has been on a US list of people "linked to terrorism" since shortly after the 9/11 attacks in 2001.
Analysts say the administration in Adado - a town about 500km (310 miles) north of the capital, Mogadishu - where Mr Aweys arrived earlier in the week, does not want to provoke clashes.
Mr Aweys left al-Shabab territory after factions within the al-Qaeda linked group clashed last week - the first deadly infighting since it launched an insurgency in 2006.
Elders from Mr Aweys' Haber Gedir clan, which is powerful in the Galmudug region, told the BBC they had been trying to mediate his surrender after his arrival in Adado.
They do not officially represent the UN-backed government of President Hassan Sheikh Mohamud, though it seems likely he is fully aware of the negotiations taking place, the BBC's international development correspondent Mark Doyle says.
The elders told the BBC Somali Service that negotiations with the al-Shabab commander had so far failed.
Mr Aweys denied that he had left al-Shabab and refused to go to Mogadishu, join the government or enter mediation talks with the government, they said.
Analysts say if the split within al-Shabab is serious, Mr Aweys may try to leave the country.
If he stays in central Somalia he is at risk of capture from Ethiopian troops, who back the Somali government, they say.
Al-Shabab, which means "The Youth", is fighting to create an Islamic state in Somalia - and despite being pushed out of key cities in the past two years still remains in control of smaller towns and large swathes of the countryside.
It was formed in 2006 as a radical offshoot of the now-defunct Union of Islamic Courts, which was led by Mr Aweys and for much of that year controlled Mogadishu and many southern and central areas.
The exact cause of the al-Shabab split is not known, but there has been a long-running internal power struggle between its leader Ahmed Abdi Godane and those seen as more moderate who oppose links with al-Qaeda, analysts say.
There are conflicting reports about the fate of the second-in-command - Ibrahim Afghan, the al-Shabab founder - following last week's fighting. Initially, sources told the BBC he had been captured and was in al-Shabab detention; subsequent reports in local media say he has been executed.
Some 18,000 African Union troops are in Somalia supporting the government of President Mohamud who was elected by MPs last September.
His administration is the first one in more than two decades to be recognised by the US and the International Monetary Fund (IMF).