An explosion on a speedboat in Bali left two foreigners dead and 18 other tourists injured Thursday, sparking dramatic scenes as rescuers rushed to haul stunned and bloodied holidaymakers off the vessel.

Dazed passengers, many covered in cuts and bruises, were taken to medical centres on the Indonesian holiday island after the blast, with TV footage showing them being carried on stretchers to ambulances and lying in hospital beds.

An Austrian woman was killed along with a second female foreigner, whose nationality was still being verified. Nationals from Briton, France, Italy, Portugal, Ireland and Spain were also on the boat at the time of the blast.

It appeared to be an accident with the explosion occurring in the fuel tank. The bomb squad was initially deployed to the scene on an island that has suffered bloody Islamist militant attacks in the past, but authorities quickly ruled out an attack.

Indonesia has a poor maritime safety record and regularly suffers fatal boat accidents but serious incidents around Bali -- which attracts millions of foreign visitors each year -- are rare.

The speedboat, which was carrying some 30 foreign tourists and four crew, had just left Padang Bai port in eastern Bali on Thursday morning when the blast occurred.

"The explosion happened five minutes after the boat departed," local police chief Sugeng Sudarso told AFP, adding the vessel had been about 200 metres (yards) from the port.

One woman died from head injuries soon after the blast while the Austrian woman died later in hospital, he said.


Poor safety record

Sudarso said he believed a malfunctioning battery near the fuel tank may have caused the accident.

"Based on the testimony (from passengers) and from what I saw at the scene, the explosion came from the fuel tank," he said.

"Above it was a battery, maybe there was a short circuit that affected the fuel tank."

The British embassy in Jakarta said it was providing assistance to those affected by the explosion.

The Indonesian archipelago of more than 17,000 islands is heavily dependent on ferry services but the industry has a poor safety record and fatal accidents are common.

Last year, dozens of tourists were injured when small explosions hit a ferry crossing between Bali and the neighbouring holiday island of Lombok.

The explosions, determined to be an accident, were thought to have come from the fuel tank of the ferry, which was carrying 129 passengers, most of them tourists.

However fears have also been growing in Indonesia that radicals who have headed to fight with the Islamic State group in the Middle East could encourage supporters back home to mount attacks, or may do so themselves on their return.

In January, a gun and suicide bomb attack claimed by IS in the capital Jakarta left four attackers and four civilians dead.

Bali has been attacked by Islamic radicals before. In 2002, more than 200 people, mostly foreign tourists, were killed in bombings on the island.

A sustained crackdown following the Bali bombings had weakened the most dangerous networks but IS has proved a potent new rallying cry for the country's extremists.

A pocket of Hinduism in Muslim-majority Indonesia, Bali attracts millions of foreign visitors every year due to its palm-fringed, tropical beaches and picture-postcard temples.