Some people reportedly climbed 18ft trees to escape the tsunami and survived.
Amateur footage shown by TV stations showed waters crashing into houses along Palu's shoreline, scattering shipping containers and flooding into a mosque in the city.
Rescuers are scrambling try to find trapped victims in collapsed buildings where voices could be heard screaming for help after a massive natural disaster in Indonesia spawned a deadly tsunami two days ago that has left at least 450 dead.
Nugroho described the damage as "extensive", adding that thousands of houses, hospitals, shopping malls and hotels had collapsed, while a bridge had also been washed away.
Photos confirmed by authorities showed bodies being lined up along a street Saturday, some in bags and some with their faces covered with clothes.
The chief of the meteorology and geophysics agency, Dwikorita Karnawati, said the tsunami waves were up to 3 metres (10 feet) high.
Indonesia's meteorological agency has been criticised for its response but officials said the waves struck while the warning was in place.
Communications with the area were hard because power and telecommunications were cut, hampering search and rescue efforts.
"This is already a tragedy, but it could get much worse", 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", Red Cross said.
Some government planes carrying relief supplies managed to land at the main airport in Palu, although officials said it would likely remain closed to commercial flights for days.
President Joko Widodo is scheduled to visit evacuation centres in Palu on Sunday.
The U.S. Geological Survey put the magnitude of the second quake at a strong 7.5, after first saying it was 7.7.
"Canada is deeply saddened by the loss of life and bad destruction wrought by the powerful natural disaster and tsunami that hit Indonesia yesterday", Global Affairs Canada said in a statement.
Paul Pogba watches Manchester United's defeat at Old Trafford
City was Lampard's last English team after spending most of his career at Chelsea , where Mourinho had two spells as manager. Manchester United have been fairly successful in the Carabao Cup over the past few years.
A tsunami caused deaths when it hit a small city on the Indonesian island of Sulawesi on Friday after a major quake offshore, collapsing buildings and cutting off power.
Palu was hit by tsunami in 1927 and 1968, according to BNPB.
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 natural disaster that killed more than 430 people.
Dozens of people were reported to be trapped in the rubble of two hotels and a mall in the city of Palu, which was hit by waves as high as six metres (20 feet) following the 7.5 magnitude quake on Friday.
"When the (tsunami) threat arose yesterday, people were still doing their activities on the beach and did not immediately run and they became victims", agency spokesman Sutopo Purwo Nugroho said on Saturday.
The Ministry of Information reported the official death toll from the quake and tsunami at 405, with all the fatalities coming in Palu.
People including dancers were still busy on the beach in Palu (population: 335,000), preparing for a festival, and were caught when waves up to 3m in height swept in.
The death toll was at least 420, state media said Sunday, as rescuers scrambled to reach the stricken region and survivors helped to retrieve the remains of those killed.
The waves which hit Palu were as high as six meters.
The disaster agency has not been able to get any information from the fishing town of Donggala, 27 km (16 miles) away from the epicenter of the quake.
A YOUNG air traffic controller who sacrificed himself to guide an aircraft to safety during Indonesia's devastating 7.5 natural disaster and tsunami has been hailed a hero.
He said: "There was no time to save ourselves".
"We need tents, medicines, medical personnel, tarpaulins, blankets and more of other things", he said. "All we knew is that 24 guests were successfully evacuated and one has died", hotel owner Ko Jefry told Metro TV on Saturday night.