WASHINGTON (Reuters) - A unit of Botox maker Allergan Plc (>> Allergan, Inc.) 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.

In a statement on Tuesday, the SEC said that the disclosure failures occurred in the months after the company received a tender offer from Valeant Pharmaceuticals International (>> Valeant Pharmaceuticals Intl Inc) and co-bidder Pershing Square Capital Management, the hedge fund run by Bill Ackman.

Allergan resisted a seven month-long hostile pursuit by Ackman and Valeant, and in November 2014 announced it had accepted a $66 billion takeover bid from Actavis.

According to the SEC, Allergan previously told investors that Valeant's bid was inadequate and that it was not in merger talks.

In fact, the SEC said Allergan did have merger talks with an unnamed North Carolina company that it never disclosed. After those failed, the SEC said, Allergan did not provide timely disclosures about its talks with Actavis.

In a statement, Allergan Plc spokesman Mark Marmur said the company's wholly owned subsidiary, Allergan Inc, agreed as part of the settlement not to engage in future violations and that the SEC had not accused the subsidiary of any intentional wrongdoing.

He added that the SEC had not charged the parent company and that the filings at issue pre-dated Allergan's acquisition by Actavis.

(Reporting by Sarah N. Lynch; Editing by Andrew Hay and Phil Berlowitz)

By Sarah N. Lynch