Omar Hassan al-Bashir's address to supporters on the outskirts of Khartoum was short on detail and made only a glancing reference to recent unrest but was notable for its disarming rhetoric.

"We open the door for freedom. We have nothing to fear from freedom ... Freedom is guaranteed by the constitution," Bashir told the crowd.

"Anybody who wants to make chaos, we will deal with him according to the law. Our doors and our hearts and our hands are open without fear."

Young Sudanese have mounted a series of short-lived demonstrations across the north in recent weeks complaining about price rises, and calling for political change and an end to human rights abuses.

Bashir's government is under additional economic and political pressure as it waits for the widely expected secession of the country's south, the source of most of its oil.

Southerners overwhelmingly voted to declare independence in a referendum in January, according to early results, in a vote promised in a 2005 peace deal that ended decades of civil war with the north.

Bashir, usually known for his more combative rhetoric, said he accepted almost all southerners had voted for separation.

He has surprised many commentators with his quick acceptance of the preliminary referendum results.