By Sami Aboudi
DUBAI (Reuters) - A Bahraini court ordered the suspension of the main Shi'ite opposition group al-Wefaq and closed down its offices on Tuesday in what appeared to be an escalating campaign against dissent in the Western-allied Gulf Arab kingdom.
The U.S. State Department said it was deeply concerned over the ruling and Bahraini opposition groups condemned the move.
Al-Wefaq's lawyer, Abdallah al-Shamlawi, said the Bahrain administrative court had also set an October date for a hearing into dissolving al-Wefaq. The move came a day after authorities detained one of Bahrain's leading rights activists.
Sunni Muslim-ruled Bahrain was rocked by mass protests by majority Shi'ite Muslims in 2011, when uprisings shook the Arab world, demanding a bigger role in running the small Gulf island, where the U.S. Navy's Fifth Fleet is based.
Al-Wefaq, which held 18 out of 40 parliamentary seats in a 2010 election, pulled out of the assembly during the 2011 crackdown against mostly Shi'ite protesters demanding greater democracy. It boycotted the 2014 election saying it believed the vote would not be free or fair.
Shamlawi said the court had ordered al-Wefaq's activities suspended and its offices closed, and set Oct. 6 as the date for a hearing into the request for the dissolution of the group, whose full name is al-Wefaq National Islamic Society.
"Two hours after a petition to stop the activities of al-Wefaq and to close its office, the administrative court swiftly approved the (justice) minister's request," he wrote on his Twitter account.
The Justice Ministry said it had filed a request to dissolve al-Wefaq, which it said "works within a political, religious and foreign framework", state news agency BNA reported.
"In view of the incitement to sectarianism and the sectarian lineup we currently see in Bahraini society... these decisions and rulings have become necessary," state news agency BNA quoted Information Minister Ali al-Rumaihi as telling the Abu Dhabi-based Sky News Arabia TV.
Residents said police have removed signboards, flags and banners from the society's offices.
Officials from al-Wefaq could not be reached for comment, but rights activists said the Bahrain Monitor for Human Rights had filed a complaint to the U.N. High Commission for Human Rights over the decision.
In Washington, State Department spokesman John Kirby urged Bahrain to reconsider its decision.
"Peaceful criticism of the government plays a vital role in inclusive, pluralistic societies," he told a briefing.
In a joint statement issued in Manama late on Tuesday, three Bahraini opposition groups said the government decision would undermine the ability of political parties to operate.
Rights groups have accused Bahrain of escalating a crackdown on the opposition over the past two years by jailing some activists and revoking citizenship of others and expelling them.
On Monday, police detained Nabeel Rajab, one of the most prominent activists in the Arab world, nearly a year after he was freed by royal pardon.
His lawyer said on Tuesday Rajab was ordered detained for a week for questioning on charges of disseminating false news.
Last month an appeals court more than doubled a prison term imposed on al-Wefaq's leader, Sheikh Ali Salman, in June last year to nine years from four.
In February, a Bahraini court sentenced Ibrahim Sharif, former head of the secular National Democratic Action Society, or Waad, to a year in jail on charges of insulting the kingdom's ruling system but cleared him of the more serious charge of calling for regime change through illegal means.
(Additional reporting by Arshad Mohammed in Washington, Editing by Dominic Evans and Gareth Jones)