Two powerful earthquakes struck Venezuela on Wednesday night, killing at least 32 people and injuring more than 700.
Authorities warned the death toll was likely to run into the thousands as the back-to-back tremors collapsed buildings across the capital Caracas and surrounding areas.
A magnitude 7.2 earthquake hit about 160km west of Caracas and it was followed less than a minute later by a magnitude 7.5 tremor, the US Geological Survey said, adding that the death toll would most likely exceed 10,000.
Interim president Delcy Rodriguez said the toll of 32 did not include casualties from La Guaira state, near Caracas and home to the capital's airport, which she described as the worst-affected area.
"Dozens of buildings have collapsed and we are currently carrying out very intense rescue efforts to save as many lives as God allows us to save," she told state television early on Thursday.
"This is a true tragedy. From here, we send our message of solidarity, and to those families who have lost loved ones, we reaffirm our condolences and our support in these difficult hours."
At least three people were killed in the Baruta district of Caracas after two buildings collapsed, the mayor said. In the neighbouring Chacao district, one person was killed and four buildings collapsed, mayor Gustavo Duque reported.
"We have buildings, homes and houses which have collapsed, and we are taking care of things with everything we have available," interior minister Diosdado Cabello said on state television.
Footage showed emergency workers climbing through the ruins of a collapsed building in the capital as night fell, while distraught relatives sought help for loved ones believed to be trapped.
"When we went downstairs, the scene was like a horror movie," Maria Alejandra, a resident from a nearby building who did not give her surname, told Reuters.
"We had to climb over the rubble and everything. The building superintendent with the baby and all the neighbours coming down. But from that building, I only saw that one family got out."
A tsunami warning was issued after the tremors hit, but swiftly cancelled after the danger passed.
Venezuela's largest airport, in Maiquetia north of Caracas, was closed due to severe damage. Schools were cancelled for the rest of the week as authorities began assessing the scale of the destruction. Staff at Hospital de Clinicas in Caracas was asked to double up on the night shift to help treat the injured, a worker there told Reuters.
US secretary of state Marco Rubio said Washington was sending search teams, medical resources and humanitarian aid to Venezuela. President Donald Trump posted on social media that the US was "ready, willing and able to help", describing the twin earthquakes as leaving "a devastating number of deaths".
Leaders of El Salvador, the Dominican Republic and Brazil also offered support. Ms Rodriguez said she had instructed the foreign ministry to coordinate the aid offers.
Venezuela's oil infrastructure did not immediately appear to be affected. Civil protection authorities in Maracaibo, near the large oil hub of Lake Maracaibo, reported no injuries while a worker at the El Palito refinery near Morón, close to the epicentre, said there had been no damage.
British oil company Shell said all its employees in Venezuela were accounted for with no injuries. One source warned that extended power outages could affect crude output until electricity was restored.
Venezuela lies in a seismically active zone where the Caribbean Plate meets the South American Plate.
An estimated 30,000 people were killed when a powerful earthquake caused widespread destruction across the country in 1812, according to the US Geological Survey.
