|Bahraini Crown Prince Sheik Salman bin Hamad Al Khalifa waves to supporters prior to the start of the Bahrain GP last year © AP Photo/Luca Bruno
Bahrain has vowed to step up security ahead of next weekend's Grand Prix after a series of explosions, including a gas cylinder blast that set a car ablaze in the Gulf nation's financial district.
The attacks caused no injuries and limited damage, but sent a message that anti-government militants could step up violence before Sunday's Formula 1 race, the premier international event in the kingdom.
Bahrain has been racked by more than two years of unrest between the Sunni-led government and majority Shiites seeking a greater political voice.
The Interior Ministry said the four blasts happened in quick succession on Sunday evening, ending with the gas canister explosion inside a stolen car in the Financial Harbour.
Bahrain said it will provide "adequate" security to protect fans and F1 teams.