Siemens' supervisory board will discuss a possible deal with French peer Alstom at an extraordinary meeting on Tuesday, three sources familiar with the matter told Reuters.

Siemens declined to comment.

The German engineering group has made a proposal to rival an offer for Alstom made by U.S.-based General Electric. Chief Executive Joe Kaeser is due to meet French President Francois Hollande later on Monday to discuss the matter.