Death toll of the recent flood in El Salvador has increased to at least 144 people, amid ongoing rescue efforts in the flood-hit country.

Residents of the town of Verapaz recall a thundering roar as earth and boulders poured down Chichontepec volcano, burying homes and inhabitants.

Rescue workers and desperate residents are digging beneath the debris for signs of those people still missing after severe flooding and landslides left at least 144 people killed across El Salvador. Three days of national mourning are to be held for the victims.

The hill-ringed town of Verapaz is now a wasteland of fallen boulders, thigh-deep mud and broken little houses.

Rescuers used shovels and tractors to clear the river of oozing mud, search for missing people and salvage contents of ruined homes. But they had to struggle against 6-foot boulders and uprooted trees.

"We don't have enough heavy equipment to lift the rocks and look for the missing," said rescue worker Jose Arnulfo Membreno, looking sweaty and exhausted.

"I started to hear roaring noises and the ground began to shake," said resident Marlene Ramirez. "Then my windows broke and lots of mud came in. I ran outside and climbed over the wall of the house next door to get on the roof."

At least 10,000 Salvadorans are in urgent need of food aid after devastating floods and mudslides that damaged crops and destroyed homes, the UN World Food Program said on Tuesday.

HSH/AKM