The Trump administration on Friday slapped new sanctions on individuals and businesses suspected of links to Hezbollah, the Lebanese militant group the White House is hoping to isolate in its bid to curtail Iran’s influence across the Middle East.

The Treasury Department announced the measures against six people and seven businesses based in Lebanon, Iraq and West Africa,  a move officials described as a first step in a wave of actions targeting the group’s licit and illicit financial networks.

The sanctions come as the Trump administration seeks to intensify its response to Iran’s support for armed groups from Lebanon to Syria to Yemen, which the United States has long complained have attacked American interests and allies, and posed a major threat to Gulf nations.

One senior U.S. official, speaking to reporters on the condition of anonymity because he was not authorized publicly to do so, described the new measures as a blow to the Revolutionary Guard Corps and its elite Quds Force, “which uses Lebanese Hezbollah as really its main means of projecting destabilizing power in conflict zones,” including Syria, Iraq and Yemen.  

The individuals and businesses sanctioned are believed to be linked to Adham Tabaja, a businessman who controls a real estate empire in Lebanon and who officials described as a senior Hezbollah financier. Tabaja has been the target of previous U.S. sanctions.

The new sanctions reach far beyond Lebanon, targeting businesses in Sierra Leone, Ghana and Liberia that officials say sit at the nexus of Hezbollah’s cash flows.

While the U.S. government has used sanctions for years as part of an attempt to constrain Hezbollah’s activity, officials acknowledge the challenge they face because of Iran’s continued support for the group. U.S. officials say Tehran provides Hezbollah an estimated $700 million a year.

They must also grapple, senior officials said in describing the new sanctions, with the fact that Iran and Hezbollah may prioritize financial backing for militant activities even when overall resources decline.

It’s not clear what effect such financial measures may have for the people and businesses identified on Friday. What has had a clear impact on Hezbollah’s finances, the officials said, is the group’s militant activities in Syria, where it has been deployed in support of Syrian President Bashar al-Assad. Hezbollah militants have taken significant losses in Syria, and the conflict has exacted a major toll in terms of manpower and weapons, and pension costs for those killed.