The ranking member of US Senate Foreign Relations Committee says the seizure of two Greek vessels by Iran’s Revolutionary Guard is yet another appalling example of Iran’s regional terrorism.

Idaho’s Republican Senator Jim Risch said in a tweet on Tuesday that “The Biden Admin must prioritize efforts to address this egregious behavior, which continues to threaten the US, its partners, and freedom of navigation everywhere.”

On Monday, US Secretary of State Antony Blinken condemned the "unjustified seizure" of the Greek-flagged vessels, saying, "Iran's continued harassment of vessels and interference with navigational rights and freedoms are a threat to maritime security and the global economy.”

France has also denounced the capture of the oil tankers in Persian Gulf waters, urging the Islamic Republic “to immediately release the crews and vessels."

The European Union also issued a statement on Sunday to express its serious concern to the Islamic Republic following the capture of the oil tankers, and called for transparency, de-escalation and a fast resolution of the issue.

On Friday, Iran’s Revolutionary Guard seized the tankers in helicopter-launched raids in the Persian Gulf about a week after the confiscation of Iranian oil from a tanker held off the Greek coast and its transfer to the US.

Iran said on Saturday that the crew of two Greek tankers had not been detained and are on board their vessels.