The Allergan logo is seen in this photo illustration November 23, 2015. REUTERS/Thomas White/Illustration/File Photo

(Reuters) - Botox maker Allergan Plc is in talks to acquire Shire Plc, competing against Japan’s Takeda Pharmaceutical Co Ltd for the London-listed drugmaker, two sources familiar with the matter said on Thursday.

It is not clear whether Allergan has submitted an offer, and there is no certainty of a bid, the sources said. Shire on Thursday said it had rejected an offer worth around $61 billion from Takeda.

The sources asked not to be identified because the matter is confidential. Allergan declined to comment, while Shire and Allergan did not immediately respond to requests for comment.