A global terror-finance watchdog agency is set to blacklist Iran, broadening a U.S. effort to isolate Tehran financially and potentially straining the already sanctions-battered Iranian economy.

Iran’s blacklisting by the Paris-based Financial Action Task Force is expected to take place Friday and comes after European governments decided to join the U.S., according to American and allied officials.

The task force’s decision will place financial transactions with Iran under additional scrutiny and escalate the pressure on the dwindling number of banks and businesses still dealing with the Islamic Republic to cut their ties.

The blacklisting marks a step forward in the U.S. campaign to use sanctions to compel the Iranian government to end its support for terrorist groups and eliminate its nuclear program. Most Western banks have already severed links with Tehran in response to the U.S. sanctions, which have also drastically cut Iran’s oil sales—its largest revenue source—weakened its economy and helped fuel street protests against the government.

European governments declined to join the U.S. pressure campaign in an effort to save the multination Iran nuclear accord, from which the Trump administration withdrew in 2018.