Russian natural gas deliveries to Germany via the Yamal-Europe pipeline fell sharply on Saturday, according to data from the operator Gascade.
This adds pressure to an already tense market and as Europe heads towards peak demand for the winter.
It was not clear why flows through the gas pipeline, one of the main routes for Russian gas exports to Europe and which runs through Belarus, decreased.
European gas prices have soared this year as demand increased strongly globally in the post-pandemic recovery.
Russia, a key supplier to Europe, has said that supplies under long-term agreements were fully met, but has not added volumes for the spot market.
Gazprom ships gas to Europe via various routes and is reserving additional capacity, or volumes in addition to firm contracts, at auctions for delivery through Ukraine and to Germany via the Yamal route.