Thirteen Bahrainis were sentenced to life in prison after they were convicted of taking part in an illegal protest.

Thirteen Bahrainis were sentenced to life in prison after they were convicted of taking part in an illegal protest, their lawyer said on Monday.

The protesters were also accused of trying to kill two policemen by attacking their vehicle.

Another man was jailed for 10 years over the same attack and protest - one of a string of clashes that have continued to erupt since demonstrators took to the streets in 2011 to demand more social justice in the Western-allied kingdom.

The sentences, handed out on Sunday, come days ahead of Bahrain's Formula One Grand Prix - an annual event which has been cancelled once, then staged amid heavy security measures since the demonstrations began.

The island kingdom, home to the U.S. Fifth Fleet, quelled early mass protests with help from Saudi Arabia forces.

Bahraini media said Sunday's defendants were accused of attacking two officers in March 2012 as young men threw Molotov cocktails at police during a protest in the village of Bilad al-Qadeem.

Lawyer Mohammad al-Tajer said he would file an appeal.

"Of course I am going to ask for an appeal. Most of the accused didn't even admit that they committed the crime," Tajer told Reuters, adding that the accused ranged in age from 16-34.

Last week, the country's criminal court sentenced 26 Bahrainis to 10 years in jail each for attacking a police station in Sitra in Bahrain's northeast, a defense lawyer said.

Two more Bahrainis were given three-year jail sentences for possessing flammable containers, he said.

Unrest in 2011 forced the cancellation of the annual Grand Prix, but the event went ahead in 2012 and 2013, alongside unrest. The next race is due to take place on April 4-6.