WASHINGTON: The U.S. Treasury, moving to boost pressure on Hezbollah, imposed sanctions on Wednesday against two people and three firms that Washington accuses of being involved in schemes to help the armed Shi'ite group backed by Iran evade American sanctions.

The Treasury's Office of Foreign Assets Control (OFAC) said it was targeting Belgium-based Wael Bazzi because he acted on behalf of his father Mohammad Bazzi, a Hezbollah financier.

OFAC also took action against two Belgian companies and a British-based firm controlled by Bazzi.

In addition, the US Treasury designated Lebanon-based Hassan Tabaja, who it said had acted on behalf of his brother Adham Tabajha, also a Hezbollah financier. The U.S. action freezes their assets and property and prevents U.S. citizens and businesses from dealing with them.

The two men and three businesses were targeted for sanctions under US regulations aimed at suspected terrorists or those who support them, the Treasury said in a statement. Hezbollah is considered a foreign terrorist organization by the United States.

"Treasury is relentlessly pursuing Hezbollah's financial facilitators by dismantling two of Hezbollah's most important financial networks," Treasury Undersecretary Sigal Mandelker said in a statement.

"By targeting Hassan Tabaja and Wael Bazzi and their European-based companies, this administration is continuing to disrupt all avenues of financial support relied upon by Hezbollah," he said.

The US State Department earlier this week offered a reward of up to $10 million for information that could help disrupt Hezbollah's financing.

The move to boost pressure on the group comes at a time of growing US concern about its role in the Lebanese government. Hezbollah's regional clout has expanded as it has sent fighters to Middle East conflicts, including the war in Syria, where it supported President Bashar al-Assad.