Feb. 6 (UPI) -- Six U.S. oil executives held in Venezuela have been moved to the country's infamous Helicoide prison, the State Department revealed Thursday.
In a briefing with reporters, Special Representative for Venezuela Elliott Abrams said the State Department has learned that the oil executives known as the "Citgo 6" were rounded up Wednesday by SEBIN, the nation's intelligence agency, and transported to the prison in the capital Caracas.
"We condemn this cruel and indefensible action and demand that their long, unjust detention come to an end and they be allowed to leave Venezuela," Abrams said during the briefing.
The five dual U.S.-Venezuelan citizens and one U.S. permanent resident are employees of the Houston-based oil refiner Citgo, which is owned by Venezuelan state-run PDVSA.
The six men were arrested in November 2017 and charged with corruption, which they deny. In December, after spending more than two years in a military intelligence facility, they were moved to house arrest, according to Share America, which is managed by the State Department.
Abrams said the men were under house arrest in their own houses but that they were under constant surveillance and that their residences were most likely bugged.
News of the roundup comes on the heels of President Donald Trump honoring opposition leader Juan Guaido -- who has been trying to oust embattled Venezuelan President Nicolas Maduro for over a year -- in his State of the Union address on Sunday and then hosting the National Assembly leader to a state visit on Wednesday.
According to one of the men's legal representatives, the Citgo 6 were removed without warning or judicial order and are being held in the same cell.
"Lawyers and relatives were not informed and they only information shared by the SEBIN officials on duty was that [they were taken away 'for medical checks,'" the legal team said in a statement, CNN reported.
Abrams said he would not speculate on why the roundup occurred but said "the timing is suspicious."
During their previous detention, Abrams said the State Department had concerns over the men's health as it was unknown if they had access to doctors or medicine and that it takes their current situation "very seriously." He added they have made "a number of efforts" Thursday to gain information about their condition and gain their release from prison.
The United States has repeatedly escalated pressure on Maduro to step down to instigate a Democratic transition in the socialist nation since his re-election was deemed illegitimate in 2018. Guaido, who is the head of the National Assembly, which is the last bastion of democracy in Venezuela, appointed himself interim president in early 2019.
The United States is one of nearly 60 mostly Western democracies to back Guaido's claim and has repeatedly imposed sanctions against the Maduro regime.
However, despite the political and financial pressure, he has maintained his grip on power with the support of Russia and Cuba, the State Department has said.
On Wednesday prior to the arrests, a senior administration official said they were planning to increase their maximum pressure campaign on Maduro.
"You'll see some impactful measures within the next 30 days, which will be very important and further crippling on the Regime.
On Thursday, Abrams warned Russia that they may soon learn that its support of Maduro "will no longer be cost-free."
"You will see steps unfold in the coming weeks that demonstrate the seriousness of our intentions in Venezuela," he said.
Citgo has been contacted for comment.