Tropical Storm Amanda, the first named storm of the season in the Pacific, killed at least 14 people as it lashed El Salvador and Guatemala on Sunday amid flooding and power outages.
El Salvador's President Nayib Bukele declared a state of emergency for 15 days to cope with the effects of the storm, which weakened later in the day as it moved into Guatemala.
The fatalities were all recorded in El Salvador, interior minister Mario Duran said, warning that the death toll could rise.
Amanda knocked down trees, triggered flash floods and landslides, caused power outages, and damaged about 200 homes, the head of the Civil Protection Service William Hernandez said.
One person is still missing, senior government official Carolina Recinos added.
San Salvador Mayor Ernesto Muyshondt said half of those killed died in the capital.
"We are experiencing an unprecedented situation: one top-level emergency on top of another serious one," he said, referring to the coronavirus pandemic.
About 4,200 people sought refuge in government-run shelters after losing their homes or being forced to leave because they were in high-risk areas, Muyshondt added.
In some flooded areas, soldiers worked alongside emergency personnel to rescue people.
"We lost everything, we've been left with nowhere to live," said Isidro Gomez, a resident of hard-hit southeastern San Salvador, after a nearby river overflowed and destroyed his home.
Another victim, Mariano Ramos, said that at dawn residents of his San Salvador neighborhood were slammed by an avalanche of mud and water. An elderly man died in the area, officials said.
El Salvador's Environment Ministry warned residents of the "high probability" of multiple landslides that could damage buildings and injure or kill people.
Nearly 90 percent of El Salvador, population 6.6 million, is considered vulnerable to flooding and landslides due to its geography.
In neighboring Guatemala, officials said roads had been blocked by at least five landslides and some flooding was reported, but no evacuations were underway.
Even though Amanda weakened to tropical depression status, Guatemalan officials warned that heavy rain would continue, with swollen rivers and possible "landslides affecting highways ... and flooding in coastal areas."