MANAMA (Reuters) - Bahrain's public prosecutor has charged the head of the main Shi'ite opposition group with insulting the interior ministry, state news agency BNA said on Sunday, in a move that could further unsettle the Gulf island state.
Sheikh Ali Salman, secretary-general of the al-Wefaq Islamic Association, was the most senior opposition figure charged since majority Shi'ites began protests in 2011 to demand political reform and a greater role in running the country.
The U.S. Fifth Fleet is based in Bahrain, a key regional ally of the West, which is ruled by the Sunni Muslim Al-Khalifa dynasty.
Minister of State for Information Affairs Samira Rajab said the Wefaq leader was suspected of "denigrating and disparaging the interior ministry" by alleging human rights violations by the police against protesters.
Ali Salman was released on Sunday after five hours of interrogation about an opposition display which Bahraini authorities closed down last week, saying it was illegal and incited hatred.
The Arab kingdom, strategically located between Saudi Arabia and regional rival Iran, has been dogged by unrest since security forces quelled the 2011 protests.
"After questioning Ali Salman, secretary general of the al-Wefaq society, the general prosecution decided to release him ... after filing charges of insulting the interior ministry," BNA said on its website.
Sheikh Salman said the questioning centred on a speech he made at the exhibition opening.
"Summoning the general secretary of a top political society which gained the votes of more than 60 percent of the population (in the last parliamentary election) is a clear violation of our political work and our freedom," Sheikh Salman told Reuters.
"This act is totally unacceptable and meaningless."
News of Sheikh Salman's questioning on Saturday sparked some protests, al-Wefaq reported on its website. A picture on the site showed small crowds marching with posters of the Wefaq leader reading: "We will sacrifice ourselves for you, We will not let you down".
"The association's exhibition showed models, miniatures and drawings alleging systematic police use of inhuman practices and human rights violations," said Rajab, the government's official spokeswoman.
"The Al-Wefaq Society secretary-general and other members (of the society?) delivered inflammatory speeches packed with lies ... which represented an affront to the status of the police," she added.
Wefaq said Al Salman's interrogation was part of a campaign of "political extortion and revenge against the peaceful opposition which is demanding democracy and rejects tyranny".
Bahraini authorities have recently summoned a number of political activists and rights campaigners for questioning over statements which they say incite violence.
Wefaq's deputy leader, Khalil al-Marzouq, was arrested in September and is on trial for inciting terrorism. He has been freed pending his next hearing on November 18.
After Marqouq's arrest, Wefaq suspended its participation in talks with the government aimed at ending the Shi'ite protests.
The talks began in February but have failed to end the political crisis, with the two sides apparently far apart on the opposition's main demand for an elected government.
Wefaq wants a constitutional monarchy with a government chosen from within a democratically elected parliament.
(Reporting by Farishta Saeed; Writing by Sami Aboudi; editing by Barry Moody)