Reince Priebus, President Trump’s Chief of Staff, issued a memo ordering an immediate regulatory freeze (link via Politico). The memo was addressed to heads of executive departments and agencies.  According to the memo:

• Except for emergency situations or other urgent circumstances relating to health, safety, financial, or national security matters, or otherwise, no regulation shall be sent to the Office of the Federal Register, or the OFR, until a department or agency head appointed or designated by the President after noon on January 20, 2017, reviews and approves the regulation.
• Regulations that have been sent to the OFR but not published in the Federal Register must immediately be withdraw from OFR review.
• For regulations that have been published in the OFR but have not taken effect, steps shall be taken, as permitted by applicable law, to temporarily postpone their effective date for 60 days.

Various news agencies described the action as typical for an incoming administration.