The U.S. is looking at sanctions that would prevent Iran from using the euro in its international business dealings.

U.S. sanctions have already cut off most of Iran’s access to international transactions using U.S. dollars and, as a result, Iran has to carry out its business in other currencies.

The Associated Press reports that U.S. senators Mark Kirk and Joe Manchin have proposed amendments to target what has been referred to as the “euro loophole.”

The move targets Iran’s access to its foreign holdings in euros and aims to block the use of the European Central Bank’s interbank payment system for Iranian business deals.

The senators are planning a vote on the amendments this weekend.

Earlier, Reuters and the Financial Times had reported that the U.S. is pressuring the EU central bank to block Iran’s access to its system. The bank has responded that it does not violate any EU sanctions with its transactions.