Force India team members were forced to flee as petrol bombs were hurled over their vehicle on their way back from the Bahrain Grand Prix track.

The four mechanics in a 4x4 were caught in the middle of an incident as police clashed with protestors.

Some tear gas fired by police entered the car, before the driver escaped through a gap in the flames on the road.

No Force India staff were hurt but two team members have asked to return home.

Analysis Dan Roan BBC sports news correspondent in Bahrain This circuit in the desert is a cocoon, shielded from the realities of this divided island. Publicly, the drivers obediently follow the FIA's orders, say the right things, and prepare to race. But Force India's traumatic experience last night has sparked a fresh sense of unease and tension among the teams. Some I've spoken to are angry with Bernie Ecclestone and Jean Todt for making guarantees over safety that now appear hollow. The expectancy is that the unrest will escalate before Sunday, and most say privately that they would rather be somewhere else, despite the renewed reassurances of the circuit authorities.

Force India driver Nico Hulkenberg questioned the decision to stage the Bahrain race, telling BBC Sport: "We shouldn't have been put in this position".

But while team-mate Paul di Resta described Wednesday's incident as "uncomfortable" he is prepared to take part if Sunday's grand prix goes ahead.

The mechanics were travelling on the main highway from the track into the capital Manama when unrest spilled into the road.

After being stopped in the road for two to three minutes, the vehicle was able to move away as part of a larger group of traffic.

Anti-government protests in Bahrain caused the 2011 race to be called off, and a number of teams expected a similar outcome for this year's race amid security concerns.

Teams and drivers are known to have private misgivings about the wisdom of racing in Bahrain amid ongoing civil unrest, but none have so far publicly questioned the decision.

The four men were said to be emotional, upset and angry with organisers that the race had been allowed to go ahead.

"We obviously sympathise with their position, their families, and we make sure it happens," said Force India deputy team principal Bob Fernley.

"But the team itself is behind the programme for Bahrain. There's no issues as far as we are concerned. We want to see it go ahead and we want to see it as part of a healing process hopefully for Bahrain."

Bahrain GP factfile First held: 2004

Last race: 2010

2010 race winner: Fernando Alonso, Ferrari

Circuit length: 5.412km

Laps: 57

2011 race: The event was called off because of anti-government protests in the Gulf state

2012 race: A number of teams expected this year's event to be cancelled, but the FIA said the race will go ahead.

Schedule: First practice begins at 0800 BST on Friday, Qualifying at 1200 BST on Saturday, Race at 1300 BST.

Bahrain circuit chairman Zayed R Alzayani said: "They weren't targeted. They just happened to be there.

"I think it's unfortunate. It's an issue of timing. It could happen in any place in the world really, getting caught up in a riot or a fight or anything."

One of the Force India team who has asked to return home was in the 4x4, which ran into trouble around 20 minutes from the circuit on the outskirts of the capital Manama.

It came at the end of the first day of work for teams in Bahrain, where they have travelled for this weekend's race following assurances from the country's authorities and F1's governing body, the FIA, that the Gulf state is completely safe.

The MRS team entered in the supporting Porsche SuperCup series has withdrawn from the weekend's season-opening race, saying it could not guarantee the safety of staff.

A spokesman for the McLaren F1 team said: "We are putting in place the appropriate security measures, which we always do at every grand prix, in accordance with local requirements."

Alzayani said there would "probably" be more violence, adding: "I can't comment on the degree of violence, whether it will be more or not - I don't have that kind of information.

"I don't think they will be within the track or close to the track, and I think they will be handled in the right way."

Alzayani said his advice to fans was "be vigilant".

"I would give them advice to enjoy the weekend," he said. "Don't be too worried and too distracted not to enjoy the weekend."

A statement from the circuit said the Force India group had driven through "an isolated incident involving a handful of illegal protestors acting violently towards police."

It added: "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 were no casualties and eyewitness reports from the scene confirmed that their vehicle had not been targeted itself."

The Gulf Kingdom's ruling royal family are being pressured to improve human rights and make reforms by the majority Shia population, who accuse the minority ruling Sunnis of discrimination.

On Friday, the FIA said it was "satisfied that all the proper security measures are in place for the running of a Formula 1 world championship event", and the race will go ahead.

However, with practice in Sakhir due to start on Friday, protests have continued in Manama with more scheduled for near the circuit on Sunday's raceday.

The Foreign Office said it would not be advising British fans to avoid travelling to the grand prix, although it was concerned about the unrest.

An all-party for group of MPs has written to F1 sponsors and urged them to boycott the event.

Some television broadcasters have decided against attending this year's race, but it is set to be shown in the UK.

Sky Sports refused to comment, while a spokesman for BBC Sport - which is due to screen highlights - said: "As the race has been officially sanctioned by the FIA we will cover the event as part of our contractual obligations.

"We take staff safety very seriously and continue to closely monitor the situation on the ground."