Manama: The Force India Formula One team will limit their involvement in second practice for the Bahrain Grand Prix on Friday and may skip the session altogether for safety reasons, deputy principal Bob Fernley said.

He said the team, some of whose members were caught in a petrol bomb incident after leaving the track on Wednesday, would take part in Saturday's qualifying and Sunday's race as scheduled however.

Asked whether the decision was because the team wanted to make sure their staff were away from the track before nightfall, when more anti-government demonstrations are expected, Fernley said that was not entirely the case.

"We'll be looking at very limited running for FP2 (free practice two)," said the Briton, speaking after his British driver Paul Di Resta was third fastest in the first practice session. "It's not necessarily a 'get home before dark'.

"We've had issues, as you all know, with things and we have to make sure that the crew are comfortable in the environment and that's what we're working on.

"But the crew are totally committed to delivering qualifying and the race. If it means we run a limited or no FP2 to achieve that, that's the decision that we will take."

Two of the team's staff, a data engineer and a radio contractor, went home to Britain on Thursday after the incident that involved four Force India members as they were returning to their hotel from the circuit.

The Bahrain International Circuit issued a statement on Thursday referring to "an isolated incident involving a handful of illegal protesters acting violently towards police.

"During this incident a Molotov Cocktail landed in the vicinity of their vehicle. After approximately two minutes, the route was cleared and the vehicle carried on its journey."

There was tighter security at the circuit on Friday with bag checks and airport-style scanners as well as scores of police cars on the highway south from Manama.

The government hopes to use the Grand Prix as a way of showing that life is back to normal after a democracy movement launched an Arab Spring-inspired uprising last year. The protests were initially crushed, but were not stamped out; demonstrations and clashes are frequent.

Wednesday's incident was the first directly involving one of the 12 teams preparing for the fourth round of the championship that local rights activists and anti-government demonstrators want cancelled.

Asked why no other teams were thinking of cutting short practice, Fernley said they had not been affected in the same way as Force India.

"Some times emotions and logic don't always add up," he declared.

The race is the first in Bahrain since 2010. Last year's was cancelled after a bloody crackdown on unrest in the tiny Gulf kingdom.

Friday is the start of the weekend in Bahrain which is also often a flashpoint for protests after prayers, since Sunday is a working day. One demonstration is scheduled to take place near the circuit later on Friday.

"I don't believe there will be any issues, there will be protests and I think it was an unfortunate incident," said Fernley. "But when it is your team that it happens to, you have to deal with it in a proper manner."