In a speech at London's Royal United Services Institute, a foreign-policy think tank, Adeyemo will make clear that U.S. officials are tracking the role crypto firms play in supporting terrorist groups as lawmakers in both parties call for a closer investigation of digital funds.

The remark comes amid a widening effort by the Treasury Department to crack down on the international financial channels that allowed Hamas to fund the deadly massacre in Israel. Treasury last week imposed sanctions on 10 Hamas members, operatives and other entities tied to the group. Treasury officials are also in Qatar this week to seek to crack down on international financial support for terrorist groups.

The Wall Street Journal, citing the crypto research firm Elliptic, reported that Hamas, Palestinian Islamic Jihad and Hezbollah raised $93 million in crypto before the attack. Although some analysts have said that figure is overstated, Sen. Elizabeth Warren (D-Mass.) cited it in a letter, signed by more than 100 members of Congress, calling for stricter regulations on crypto trading.