Venezuelan police rounded up six U.S. oil executives who have been under house arrest, hours after President Donald Trump met with opposition leader Juan Guaido in Washington.

Family members of the six executives of Citgo said they were seized from their homes Wednesday night and that they didn't know where the men were being held.

Elliot Abrams, U.S. special representative for Venezuela, said U.S. officials thought the men were being held in El Helicoide prison and were taken there by Venezuelan intelligence agents. He said the timing of their detention, just after Trump held talks with Guaido, was suspicious.

"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. "We urge the regime to release unconditionally all persons who are being detained, including National Assembly deputies."

There has been no comment from Venezuelan officials.

Citgo is a Venezuelan-owned oil company whose corporate headquarters and main refinery are based in Texas.

Police arrested the men in November 2017 and charged them with embezzlement, money laundering and corruption.

A Venezuelan court ordered them to be put under house arrest awaiting trial.

Citgo says the executives are political prisoners and that their fundamental human rights are have been violated. The company says it will continue to provide legal expenses and other support to their families.

The families have appealed to the State Department to help win the executives' freedom and also met last year with Vice President Mike Pence.

It was unclear if Trump and Guaido talked about the detained men during their meeting.