PALU, Indonesia— A French rescue team said Thursday it had detected a possible sign of life under the rubble of a hotel in Indonesia's central Sulawesi, nearly a week after it was hit by a powerful earthquake and tsunami, as the death toll rose to more than 1,500. The rescue team cautioned that other factors could cause the sensors members use to give a false result.

Philip Besson, a member of the French organization Pompiers de l'urgence, said the team's high-tech sensors "detected the presence of a victim" in the wreckage of the four-star Mercure Hotel in Palu but wasn't able to say if the person is conscious. The device can pick up signs of life, including breathing and heart beats, he said.

Nita Hamaale, whose 20-year-old younger sister is believed to be buried beneath the hotel rubble, said a translator for the French rescue team told her they didn't want to raise her hopes. The translator said it's possible other factors such as gas in the rubble could result in a false positive, Hamaale told The Associated Press.

Besson said the five-member team only had a hand drill that was not strong enough to reach the victim, who was trapped under thick concrete, and had to abandon digging as night fell. Besson said the team would bring heavy equipment early Friday to try to rescue the person.

"We have to drill through the concrete to be able to verify and access the victim," he told AP.

Rescue efforts since last Friday's quake have been greatly impeded by a shortage of heavy equipment. The national disaster agency said late Thursday that the death toll has risen to 1,558.

Agency spokesman Supoto Purwo Nugroho said the body of a South Korean man was among eight dead pulled Thursday from the wreckage of another hotel, the Roa Roa, which collapsed sideways in a heap of cement and steel. Local television said the man, the only foreigner known to have perished in the disaster, was a paraglider taking part in an event in the area.

As the search for victims continued, aid workers raced to get shelter, food, medicine and other badly needed supplies to survivors.

The Indonesian military was bringing in hundreds more troops to help with search and rescue efforts and keep order among survivors who have grown desperate six days after their lives were thrown into chaos. Hundreds of the injured and other survivors lined up on the tarmac of Palu's badly damaged airport, hoping to escape aboard military aircraft.