By Andrew Hammond

DUBAI (Reuters) - Bahrain has said it is banning opposition rallies in order to prevent disruption to traffic and street violence that are sabotaging efforts to end unrest in the Gulf Arab state.

But the opposition described the move as a new attempt to silence them.

The island state ruled by the Sunni Al Khalifa family has seen unrest since an uprising for political reforms, led by majority Shi'ites, was launched in February 2011 after revolts in Egypt and Tunisia.

The uprising was initially crushed during a period of martial law but unrest has continued with regular organized protests by opposition parties and clashes between riot police and youths who say the monarchy marginalizes them.

A senior official said the government had no new plans to ban rallies outright, but wanted to make sure they did not turn violent.

The Interior Ministry said this week it had banned a series of rallies on Thursday and Friday organized by the leading opposition party Wefaq, the latest in a series of publicly announced bans over the past month,.

It cited public interest and traffic concerns.

"Holding these marches will damage people's interests and hold up traffic," state news agency BNA said latge on Thursday, citing public security chief Tariq al-Hassan.

"The marches cannot be considered as responsible freedom of expression," it said, adding that march organizers had not been able to control them in the past.

Senior Wefaq member Abduljalil Khalil decried what he said was a new policy to end the use of the street to demand reforms.

"This will lead to more escalation since people now feel no hope. There is no chance to practice their freedom, they have cornered everybody now," he said.

Amnesty International criticized the bans on Thursday, saying the government was violating fundamental rights. A government statement said the interior ministry was working on identifying "approved locations" for rallies.

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

Shi'ite protesters operating under the banner of an underground group called the February 14 Youth Coalition throw petrol bombs at police in clashes in Shi'ite neighborhoods. Police say many of their men have been burned by these bombs and wounded by homemade explosive devices.

Penal code changes published on Thursday specified sentences of seven and 10 years in jail for causing permanent injury to security personnel or life imprisonment for accidental death.

Opposition activists say youths are retaliating for heavy use of teargas to break up demonstrations against a government dominated by the Khalifa family.

They say over 45 people have died because of police tactics since martial law ended over a year ago. The government questions the causes of death. Continued...