The US, Britain, Norway and Canada have all expressed concern over Sudan's "return to military rule", reports AFP news agency.

"Allowing security forces to act with impunity will further erode human rights, governance and effective economic management" in Sudan, AFP quotes a joint statement by the four countries' Khartoum embassies as saying.

"The return to military rule does not create a conducive environment for a renewed political dialogue or credible elections."

"We also note continuing reports of unacceptable use of live fire, beating of protesters and mistreatment of detainees," said the statement.

President Omar al-Bashir declared a state of emergency on Friday in an attempt to end a 10-week uprising that has threatened to bring an end to his 30 years in power.

He dissolved the government and banned public protests.

The state of emergency comes with extra powers for the security services.

Since the state of emergency was announced, hundreds of pick-up trucks with mounted machine guns have been deployed onto Khartoum's streets.