31 C.F.R. § 598.404
Setoffs prohibited
A setoff against blocked property (including a blocked account), whether by a U.S. bank or other U.S. person, is a prohibited transfer under § 598.202 if effected after the effective date.
A setoff against blocked property (including a blocked account), whether by a U.S. bank or other U.S. person, is a prohibited transfer under § 598.202 if effected after the effective date.