Havana, Cuba - Two US Democratic lawmakers have met Cuba's president in the first congressional visit since Washington imposed an oil blockade against the island, a measure they denounced as "economic bombing."

US Representatives Pramila Jayapal and Jonathan Jackson concluded a five-day trip to Cuba on Sunday as President Donald Trump has stepped up pressure on the communist government.

Cuban President Miguel Diaz-Canel on Monday posted photos of his meeting with the lawmakers on social media platform X.

Diaz-Canel said that during the meeting he denounced "the criminal harm" caused by the US blockade as well as Washington's "threats of even more aggressive actions."

The Cuban leader, who confirmed in March that US and Cuban officials had held talks, reiterated his government's willingness to "engage in serious and responsible bilateral dialogue, and finding solutions to existing differences."

In a statement, the US lawmakers said the de facto blockade imposed by Trump in January was "illegal" and "causing untold suffering to the Cuban people."

"This is cruel collective punishment -- effectively an economic bombing of the infrastructure of the country -- that has produced permanent damage. It must stop immediately," the statement said.

Trump effectively prevented oil exports to Cuba in January after US forces ousted Havana's main regional ally, Venezuela's socialist leader Nicolas Maduro, and he threatened tariffs on countries that ship crude to the island.

The measure has deepened an energy crisis in Cuba, which has endured regular blackouts.

The US president made an exception last week, allowing a Russian oil tanker to deliver 730,000 barrels of crude to Cuba.

In an interview with Belly of the Beast, a Cuba-focused website, Jayapal described visiting a maternity hospital where they saw premature babies in incubators.

"It's like an act of war because we're refusing to allow fuel to come in to power the generators, to get medicines to people, to allow the doctors and medical professionals to go to the hospital," she said. "It's just cruelty and collective punishment."

They noted that Cuba's government allowed an FBI team to visit Cuba last week to conduct an independent investigation into a deadly shooting involving a US-registered boat.

They also noted that the government pardoned more than 2,000 prisoners last week. No political prisoners have been released so far, however.