Executive Order 13224 and the prohibited parties list of the Office of Foreign Assets Control (OFAC) is in effect now. It has civil and criminal penalties.
The Money Laundering Control Act, a criminal statute, is in effect now.
The USA PATRIOT Act/Bank Secrecy Act, which requires certain anti-money laundering compliance activities, will result in regulations directly affecting the real estate industry within a matter of months.
See the viewpoints of two legal eagles from Holland & Knight in the DC area on this very topic.