BALI, Indonesia -- Indonesian police said Friday there is no indication that a terror attack was the cause of a tourist boat explosion in Bali that killed two people and injured about 20 others.

Karangasem district police chief Sugeng Sudarso said investigators believe a fuel leak below deck caused a buildup of fumes that ignited, though the finding is provisional.

Sudarso and Bali police spokesman Made Sudana said there was no sign of terrorism and a bomb squad did not find any explosive materials.

Investigators have recovered body parts and continue to examine the boat, Sudarso said.

Police on the popular tourist island of Bali have given conflicting accounts of the nationalities of the two women killed in Thursday's explosion but now say one was from Austria and the other from Spain.

Sanglah Hospital gave the same information for the nationalities and said the Austrian woman was 28.

About 20 people were injured on the speedboat that was ferrying tourists from Bali to neighbouring Lombok.

Bali became a byword for tragedy in 2002 when bombings by Jemaah Islamiyah militants killed 202 people, mostly foreigners.

A sustained security crackdown since then has weakened JI but counter-terrorism officials say there is still a threat of attacks from radicals inspired by the Islamic State group.