Just days before Bahrain hosts the second of the pre-season tests, a policeman has been killed in a bomb blast.

It is understood the officer was killed in an incident in the village of Dair, just twenty-five miles from the Bahrain International Circuit, during a protest to mark the third anniversary of the 2011 uprising.

"There was an explosion that damaged a bus carrying policemen in Dair," said the interior ministry in a statement.

"Two policemen were injured in a terrorist explosion," it added, admitting that one of them later died of his injuries.

On Friday, demonstrators were prevented from reaching the site of what was the Pearl Roundabout, the iconic focus of the original protests in 2011 when protestors called for an end to discrimination against the majority Shia community.

Police have said they arrested 26 protestors on Friday after arresting 29 on Thursday, the charges including vandalism, illegally blocking roads to disrupt traffic and attacking police with firebombs.

After much dithering by the sport's powers that be, the 2011 event, which was initially moved to a later slot in the calendar, was cancelled by the promoters. The race went ahead in 2012 despite the unease of some drivers and team personnel and calls from human right activists.

Now back on the calendar, and out of the media spotlight, Bahrain is to host two of this year's three pre-season tests, the island state able to guarantee weather that Spanish tracks such as Barcelona and Jerez can only dream of at this time of year. This year's race has also been given an evening slot, such is the sport's confidence in the situation there.

Whilst this latest incident might be a minor blip, with all the teams attending the tests at the Bahrain International Circuit, and security not as heightened as it would be at the time of the Grand Prix, many will be keeping a watching eye on developments.

While the Bahraini authorities will want to clamp down on the protestors as quickly and discreetly as possible, the protestors will be fully aware of the fact that, courtesy of the tests, the media spotlight will be on the country once again thus affording them highly valuable publicity opportunities.

Chris Balfe