The death toll in Ecuador’s most powerful earthquake in decades has risen to about 350, the government has said.

Teams from Switzerland, Spain and several Latin American countries have arrived to join the local search effort.

More than 2,000 people were injured in the quake.

Ecuador’s President Rafael Correa warned that the death toll was likely to rise, and said there were still people alive under the rubble of collapsed buildings. He said it was the biggest tragedy to hit Ecuador in the past seven decades.

The president visited some of the people affected by the disaster after cutting short a visit to Italy to return to his home country.

“I fear that figure will go up because we keep on removing rubble,” Rafael Correa said in a TV address.

“There are signs of life in the rubble, and that is being prioritized.”

Rafael Correa warned that the quake will cost Ecuador billions of dollars. It comes at a time when the oil-producing country is already reeling from the slump in global crude prices.

Correspondents say that while Ecuador’s energy industry survived the quake mostly intact – the main refinery of Esmeraldas was closed as a precaution – exports of bananas, flowers, cocoa beans and fish could be delayed because of impassable roads and hold-ups at ports.

Foreign Minister Guillaume Long praised those nations which had contributed to the rescue effort.

Guillaume Long tweeted that as many as 120 mobile rescue teams would be on the ground by Tuesday morning.

The magnitude-7.8 quake struck on April 16. Coastal areas in the north-west were closest to the epicenter. There have been about 230 aftershocks across the country.

A state of emergency has been declared and some 10,000 troops and 3,500 police have been deployed in the affected areas.

In Pedernales, close to the epicenter, as many as 400 people are feared dead. Mayor Gabriel Alcivar said the “entire town” had been flattened.

“Pedernales is devastated. Buildings have fallen down, especially hotels where there are lots of tourists staying. There are lots of dead bodies,” he told local media.

“We’re trying to do the most we can but there’s almost nothing we can do,” Gabriel Alcivar added, warning that looting had broken out.

More than 600 people have been treated for injuries at tents in the town’s football stadium, with many others taken by ambulance or helicopter to regional hospitals. The stadium also served as a makeshift morgue, Reuters reported, with at least 90 bodies taken there.

Many residents of the town are due to spend the night sleeping outside on mattresses in muggy and tropical conditions and afraid of more aftershocks.

Firefighters conducted rescue operations in destroyed buildings, demanding silence so they could listen for cries for help.

Meanwhile, queues for essential supplies such as bottled water, blankets and food formed around the stadium’s walls, as residents complained that electricity shortages were preventing them from using mobile phones to contact loved ones.

More than 1,000 policemen are patrolling the streets of Pedernales ahead of an expected visit by the president.

The quake cut power supplies along the coast. With too few emergency shelters, many residents have spent two nights out in the open.

In Portoviejo, where looting was reported, about 400 residents gathered at the city’s former airport to queue for water and other supplies.

The US Geological Survey (USGS) said the earthquake struck at a fairly shallow depth of 11.9 miles, about 16 miles from Muisne in a sparsely populated area.

The quake was also felt in neighboring Colombia.

Scientists say there is no connection between the quake in Ecuador and a severe tremor in southern Japan, which also occurred on April 16.