BERLIN, Jan 18 (Reuters) - Germany on Monday demanded the release of Kremlin critic Alexei Navalny, detained on Sunday on his return to Russia, and said it would discuss his case with its European partners.

Asked whether Navalny's detention was cause for Chancellor Angela Merkel to reconsider her support for the Nord Stream 2 gas pipeline from Russia to Europe, government spokesman Steffen Seibert told a regular government news conference:

"The position of the federal government on the Nord Stream 2 project, which is a commercial project, has been presented here often enough and has not changed." (Writing by Paul Carrel; editing by Thomas Seythal)