Jakarta, Sep 30 (IANS): The death toll from a tsunami that hit Indonesia's island of Sulawesi triggered after a 7.5-magnitude quake increased to 405 on Sunday, as rescue workers continued a desperate search for survivors, according to the country's disaster management agency.

After the earthquake hit the island on Friday, water smashed into buildings and swept away homes in the coastal city of Palu, home to 350,000 people, reports CNN.

Indonesian Disaster Management Agency spokesman Sutopo Purwo Nugroho confirmed the toll on Sunday adding that over 400 others were badly injured and many were still buried under debris.

Electricity and communications have been cut off, making it difficult to assess the damage in Palu and nearby fishing community of Donggala, Sutopo said.

"It is not just the people in the large urban areas. There are a lot of people also living in remote communities who are hard to reach" Jan Gelfand, head of the International Red Cross in Indonesia, told CNN.

With Palu airport closed, relief workers are making their way to the city by road.

"We already have people en route but you never know what damage there is to the road infrastructure," Gelfand added.

The city's authorities urged residents to not go inside their homes on Saturday night and to sleep away from buildings -- fields, roads or yards because of the danger from aftershocks.

After a local hospital was damaged, medical staff opted to treat dozens of wounded residents just outside the building, Sutopo said.

The horrific scene began on Friday when the first in a series of tremors was felt at 3 p.m., 56 km north of Palu, according to the US Geological Survey (USGS).

Three quakes of 4.9 and larger magnitudes were recorded up to three hours before the tremor near Palu.

The tremor triggered a tsunami that hit beaches in the cities of Palu and Donggala, officials said.

A series of aftershock quakes were reported in the aftermath of the quake, including a 5.8 magnitude tremor just 12 minutes later.

An early tsunami warning had been issued by the Indonesian meteorological agency, but was later lifted after the agency ascertained that the water had receded.

The quakes come a month after a trio of earthquakes hit several islands in the South Pacific and Indonesia, including Lombok, which is still recovering from the effects of an August 5 earthquake that killed more than 430 people.