U.S. diplomats are demanding that Venezuela give them immediate access to jailed oil executives who hold American passports.
The State Department said in a statement Friday that the U.S. Embassy in Caracas made the request to the government under international law.
It follows this week's arrest of six high-ranking executives from Citgo, a Houston-based subsidiary of Venezuela's state oil company. Venezuela accuses them of embezzlement stemming from a $4 billion deal to refinance bonds.
Five of the six Venezuelan executives have dual U.S. citizenship.
Oil-rich Venezuela has the world's largest oil reserves, yet low crude prices plunged the country into financial crisis.
The international scuffle could further strain relations between the Trump administration and Venezuela as socialist President Nicolas Maduro tries to refinance billions in foreign debt amid U.S. sanctions.