UPDATE 1-Allergan to pay $15 mln over failing to disclose merger talks

WASHINGTON, Jan 17 (Reuters) - A unit of Botox maker Allergan Plc will pay a $15 million penalty and admit to wrongdoing, after U.S. regulators on Tuesday accused the unit of failing to disclose 2014 merger talks with Actavis, the U.S. Securities and Exchange Commission said.