* Tens of thousands of Kuwaitis have protested since October
* Government says needs to maintain law and order
* Activists say police beat them, used tear gas without warning
Kuwaiti security forces appear to have used excessive force to disperse several largely peaceful street protests since October, Human Rights Watch (HRW) said on Thursday, citing activists, protesters and witnesses.
Tens of thousands of Kuwaitis have taken to the streets over the past two months to protest changes to voting rules used in a parliamentary election on Dec. 1 that they said would skew the outcome in favour of pro-government candidates.
The Interior Ministry justified the use of force on the grounds that protesters had blocked traffic, thrown stones at the police, and attacked them, HRW said. But participants said the demonstrations were largely peaceful.
"They said that masked riot police used tear gas and sound bombs without warning to disperse demonstrations and beat protesters while arresting them for participating in 'unauthorized protests,'" the New York-based rights group said.
Kuwait's Information Ministry, in reaction to the HRW statement, said authorities were required to maintain law and order when illegal marches and demonstrations took place.
"Kuwait has witnessed several protests in 2012 where streets were blocked and riots took place at residential areas which endangered civilians and public properties," the ministry said.
"The right to protest is enshrined in our constitution. However, protesters should be aware of both their rights and responsibilities under the law."
Although Kuwait, an OPEC member state and ally of the United States, tolerates more dissent than other Gulf Arab countries, it has been enforcing a ban on public gatherings of more than 20 people without a permit.
"Kuwait's rulers need to fully respect the right to assemble peacefully," Eric Goldstein, deputy Middle East director at HRW said in the statement issued from Beirut. "Declaring a gathering 'unauthorized' does not give police license to beat protesters."
Kuwaiti protesters have been less radical in their demands than demonstrators in other Arab countries, calling for the reinstatement of the old voting system, action against corruption and for an elected government rather than one appointed by the prime minister, who is chosen by the emir.
"The authorities should show they will not tolerate abuses by investigating all allegations of abuse by security forces and punishing those responsible for violating rights," Goldstein said. HRW also said Kuwait should increase the accountability of police by ending the use of masked anti-riot officers.
"While police agents may have legitimate reasons to mask their identities in limited circumstances, such as when conducting surveillance, policing demonstrations is not one of them."
Emir Sheikh Sabah al-Ahmad al-Sabah, who used emergency powers to change the voting system, said on Dec. 16 he supported freedom of expression and constructive criticism, but recent events had shown "aspects of chaos, breaching of the law and unguided political discourse".
The momentum of the protests has slowed since the election, with the last rally on Dec. 15 drawing several hundreds of people.