DUBAI (Reuters) - Bahrain must lift its total ban on opposition protests, which violates the right to freedom of expression and peaceful assembly, rights group Amnesty International said on Wednesday.

Bahrain, a U.S. ally which hosts the U.S. Navy's Fifth Fleet, has been in political turmoil since pro-democracy protests led by its Shi'ite Muslim majority erupted last year and were put down by the island's Sunni Muslim rulers.

On Tuesday, Interior Minister Sheikh Rashed bin Abdullah al-Khalifa said the Gulf Arab kingdom had banned all rallies and gatherings to ensure public safety and prevent violence.

He said the move was necessary because violence accompanying marches and gatherings had disrupted traffic, affected trade and the economy and damaged private property.

London-based Amnesty said the measure nullified the rights to freedom of association, expression and assembly.

"Even in the event of sporadic or isolated violence once an assembly is under way, the authorities cannot simply declare a blanket prohibition on all protests," said Hassiba Hadj Sahraoui, its Middle East and North Africa Deputy Director.

"Law enforcement officials must act to protect peaceful protesters rather than using the violent acts of a few as a pretext to restrict or impede the rights of all."

Bahrain's leading opposition party Wefaq described the ban as an attempt to silence it.

"We reject this decision and consider it against our constitutional right. There is no reason for it because all our events are peaceful," Wefaq official Sayed Hadi al-Mousawi told Reuters from Manama, adding that he feared the prohibition might lead to more tension in the street.

Britain has expressed concern over the ban and called on demonstrators to "desist from violent protest".

"A blanket ban of this nature is excessive," Alistair Burt, Minister for the Middle East and North Africa, said on Tuesday.

"Peaceful protest is a democratic right. I hope the Bahraini government will rescind this measure as quickly as possible."

Bahrain has banned a series of protests organized by Wefaq in the past few months. A senior official said in July that the government had no plans to ban rallies outright, but wanted to ensure they did not turn violent.

Since April the authorities have stepped up efforts to crack down on unrest. Activists cite an increased use of shotgun pellets, whose use officials have declined to confirm or deny.

Activists have been sentenced to jail for organizing or taking part in unlicensed anti-government protests.

The ruling Al Khalifa family used martial law and help from Gulf neighbors to put down last year's uprising, but unrest has resumed. Shi'ite protesters and police clash almost daily.

On October 19, a policeman was killed and another critically wounded in a bomb attack while on patrol in south Manama.

(Reporting by Rania El Gamal; Editing by Alistair Lyon)