Khalil al-Marzouq, of the opposition Al Wefaq party was summoned by the police and is expected to face legal charges.

A senior Bahraini opposition politician was summoned by police on Tuesday on charges of inciting “acts of terror”, in a move that could complicate efforts to end political turmoil in the strategically vital Gulf Arab kingdom.

A police statement said Khalil al-Marzouq, of the opposition Al Wefaq party, had gone to a police station in response to a summons and was “facing charges of inciting acts of terror”.

“He was then referred to the Public Prosecution where further legal procedures will take place,” a brief police statement said, without elaborating.

Persistent periods of unrest since February 2011, when an uprising led by the Shi’ite Muslim majority demanded the Sunni al-Khalifa dynasty give up power, have planted Bahrain on the front line of a tussle for regional influence between Shi’ite Iran and Sunni Saudi Arabia.

Authorities in Bahrain, which hosts the U.S. Fifth Fleet, quelled the 2011 revolt, one of a series of “Arab Spring” upheavals, but protests and clashes have persisted despite talks between government and opposition.

There was no immediate reaction from Al Wefaq to news of the charges against Marzouq, a former lawmaker who is an aide the party’s Secretary General, Sheikh Ali Salman.

But earlier, reacting to reports circulating in opposition circles that police had taken Marzouq to the public prosecution office, the party had said “such practices will only result in more anger and persistence to achieve democratic transition and build a state of justice and democracy.”

Al Wefaq, a large opposition group which says it advocates non-violent methods of activism, said in a statement the measure was part of a government project to “wipe out” political action.

This year, Bahrain passed new laws against what it called acts of terrorism, setting tougher penalties including longer prison terms and the stripping of Bahraini nationality.

The Interior Ministry said on Twitter that one of five policemen wounded in a bomb attack in Dair village north of the capital Manama in August had died of his injuries.

The ministry said at the time that security officers had confronted a “terrorist group” in the village when the homemade device exploded.

A spokeswoman for the official Information Affairs Authority said the policeman was the third to be killed by what she termed terror acts this year and the eighth since the unrest broke out in 2011.

An international inquiry commission said in a November 2011 report that 35 people had died during the uprising. The dead were mainly protesters but included five security personnel and seven foreigners.

The Bahrain opposition complains of discrimination against Shi’ites in areas such as work and public services, and is demanding a constitutional monarchy with a government chosen from within a democratically-elected parliament.

The government denies any discrimination. It has accused Iran of fomenting unrest in Bahrain, a charge Tehran denies.