Senior U.S. Treasury Department officials visited Beirut this week to urge Lebanese authorities to stem the flow of funds to Hamas through Lebanon, officials said.

Jesse Baker, the U.S. Treasury Department’s deputy assistant secretary for Asia and the Middle East, met with Lebanese politicians and financial officials on Thursday and Friday.

His visit comes as ceasefire talks between Israel and Hamas in the Gaza Strip appear to be stalled. Many fear escalation in the region, including in Lebanon, if the fighting continues during the Muslim holy month of Ramadan, which begins late Sunday. For more than five months, there have been almost daily low-level clashes between the Lebanese militant group Hezbollah, a Hamas ally, and Israeli forces.

A Treasury official who spoke on condition of anonymity said Baker shared “specific concerns” with Lebanese authorities about “the movement of Hamas funds through Lebanon and Hezbollah funds from Iran into Lebanon and then into other areas.” It called for “active measures” to be taken to combat it.

The official said the groups need financial flows to pay their fighters and carry out military operations or they cannot achieve their goals.

The Treasury official added that for Lebanon, complying with global anti-money laundering and counter-terrorism financing standards is key to attracting investment from the United States and other countries around the world and pulling the country out of a protracted crisis.

The Treasury official said Baker urged Lebanon to crack down on a host of illicit financial services companies that thrived when the country’s formal banking system collapsed during four years of economic crisis, including illegal currency exchanges and unlicensed money transfer operations.

These businesses, along with a cash economy that the World Bank estimates accounts for nearly 46% of Lebanon’s gross domestic product, provide workarounds for individuals and groups barred from the formal financial system by U.S. sanctions, including Hamas and Hezbollah. Washington considers terrorist groups.

Lebanese Hamas spokesman Walid al-Kilani said he had “no information on the matter.”

Lebanese Central Bank spokesman Halim Berti confirmed that officials from the institution had met with Baker, calling the meeting “very positive.”

He said the central bank was doing its part to supervise licensed financial services companies, but those operating without licenses “are not within our jurisdiction” and should be dealt with by law enforcement.