Riot police watch as a crowd gathers during a demonstration in downtown Tunis, January 19, 2011. [Photo/Agencies]

Underlining international concern over Tunisia, US President Barack Obama spoke to Egyptian President Hosni Mubarak about Washington's desire for calm.

At a summit in Egypt, the head of the Arab League warned the region's leaders to heed economic and political problems.

Switzerland said it was freezing assets of Ben Ali and his entourage. Tunisia's state news agency said an investigation would be launched into allegations that Ben Ali, wife Leila, and members of their families had acquired property and stocks abroad. It said there would be an inquiry into the transfer of foreign currency abroad by members of Ben Ali's extended family.

State television said the government released 1,800 prisoners serving less than six months for minor offences. It was not clear if any of these included any political detainees.

France said it had intercepted a shipment of riot gear ordered by Ben Ali just before his downfall last week.

The United Nations said it would send a team of human rights officials to Tunisia next week to advise the new coalition government.

UN High Commissioner for Human Rights Navi Pillay said she had information that more than 100 people had died in the violence. The Tunisian government puts the figure at 78.

Rating agency Moody's Investors Service on Wednesday lowered its credit rating for Tunisia, and Standard and Poor's has threatened to do so if uncertainty continues. The cost of insuring Tunisia's debt against default rose sharply.

A protester shows an empty bullet casing after riot police broke up a demonstration in downtown Tunis January 18, 2011. [Photo/Agencies]