A remote fishing area is feared to have been wiped off the map after a deadly tsunami hit Indonesia, leaving hundreds dead.

Disaster response units were struggling to get to the town of Donggala on Saturday, with communications to the area completely cut off.

Some 300,000 people live in Donggala, which along with the city of Palu is believed to be the worst affected area after a huge wave was triggered by a devastating magnitude 7.5 earthquake. Both are located on the island of Sulawesi.

At least 384 people have been killed in the disaster, officials have said, as many were swept away by huge waves reaching as high as 20ft. At least 540 people have been injured, and 29 reported missing.

Images from Palu, which has a population of 380,000, show parts of the city completely submerged in water with widespread damage to buildings. 

Sutopo Purwo Nugroho, spokesman of Indonesia's disaster mitigation agency BNPB, said casualties and the damage could be even greater in Donggala, located 190 miles north of Palu along the coastline and closer to the epicentre of the quake.

Communications "were totally crippled with no information" from Donggala, Mr Nugroho said.

The Red Cross said in a statement: "We're now getting limited communications about the destruction in Palu city, but we have heard nothing from Donggala and this is extremely worrying. There are more than 300,000 people living there."

The charity said its staff and volunteers were heading to the affected areas. "This is already a tragedy, but it could get much worse," it said.

The Indonesian vice president Jusuf Kalla has warned the death toll could rise to the thousands.