The US embassy in Khartoum called Wednesday for all sides in Sudan to avoid further violence as deadly protests sparked by fuel price hikes intensified.

"We call on all sides not to resort to force and to respect civil liberties and the right to peaceful assembly," said a US embassy statement issued in Arabic.

"In these difficult moments, it is necessary for all sides to show restraint and prudence," the embassy said.

It said it had received "regrettable reports of serious injuries and attacks on property during demonstrations which turned violent."

Three people have been killed since the protests erupted on Monday, spreading from the agricultural belt south of Khartoum to the capital and to the Darfur region in the west.

A warden's message on the embassy website warned US citizens of the risks of further protests in the greater Khartoum area.