A group of British MPs have called for the Bahrain Grand Prix to be cancelled amid unrest in the Gulf state.
A week of protests to coincide with this weekend's race began last Friday, organised by the opposition to the ruling royal family.
In a letter to F1 boss Bernie Ecclestone, the All-Party Parliamentary Group for Democracy in Bahrain said: "We request you cancel the Grand Prix.
"It is likely to attract as much negative publicity as last year."
The APPG has also written to broadcasters, teams, drivers and sponsors ahead of the Grand Prix.
The 2011 event was postponed and after month-long pro-democracy protests were crushed and at least 35 people died.
went ahead once Ecclestone and governing body the FIA said they had been assured the kingdom was safe for F1 personnel.
There are similar concerns this time around and, in a letter signed by 20 MPs, the All-Party Group asked Ecclestone to call off the Grand Prix.
"Since April 2012, many more people including children have lost their lives and the whole country exists in fear and intimidation," wrote Andy Slaughter, chairman of the Group.
"Last year's race was held under conditions of martial law. Three hundred protesters were arrested, some spending months in jail.
"I think most democratic-minded people would be appalled if you allowed the Bahrain leg of the Formula 1 championship to go ahead amidst the most atrocious human rights violations."
A report in the New York Times claimed that authorities in Bahrain were increasing security following a series of explosions in the country.
The explosions were reported to include a gas cylinder that set a car ablaze in the financial district of the capital Manama.
Meanwhile, the F1 teams say they are implementing "normal security measures" in the run-up to the Grand Prix.
Before the 2012 race, Force India mechanics were caught up in an incident in which a petrol bomb bounced off the roof of their car as protestors battled with police on the main highway from the circuit into Manama.
A day later, the team skipped the second practice session to ensure their personnel could return to their hotel before dark.
But Force India deputy principal Bob Fernley said: "Lightning doesn't strike twice in the same place. I am not expecting any issues at all."
When asked by BBC Sport if they were taking extra security measures for the race weekend, Ferrari said: "Not really. It is up to the federation (the FIA) to give us any indications as to whether extra precautions need to be taken." When asked whether the FIA had, Ferrari replied: "So far, no."
BBC Sport has also received responses from the following F1 teams:
Red Bull commented: "The team will be vigilant and take sensible precautions, but otherwise we are approaching this race in the same way we do all races."
McLaren stated: "The team will be staying very near the circuit, at a hotel that has very good security, and we feel that no extra security measures are therefore necessary for us."
Williams added: "We are adhering to our normal security measures in Bahrain and just using usual common sense, nothing more."
Mercedes said: "The safety of our employees is our highest priority and we will follow the guidance of the Foreign and Commonwealth Office (FCO) concerning travel to the region.
"We have taken similar measures to those we used last year but would ask for your understanding that we do not wish to go into specific details."