WARSAW (Reuters) - Poland's gas pipeline operator Gaz-System said on Saturday gas flows from Russia's Gazprom (>> Gazprom PAO) via Ukraine dropped 20 percent between Thursday and Friday, but supplies were now back to normal.

Gaz-System spokesman Tomasz Pietrasienski told Reuters the operator had not received any explanation from Gazprom, and that its Ukrainian counterpart Ukrtransgaz hadn't either.

Gazprom was not immediately available for comment.

"Because of low gas demand this time of the year, the possibility of reducing gas flows to storage and of using other supply routes, especially the LNG terminal, (means) the situation does not pose any threat to gas deliveries to users or system stability," Gaz-System said in a statement.

Similar shortages occurred two years ago, when Poland was at odds with Russia - its former communist master and dominant gas supplier - over the stand-off in Ukraine.

That encouraged Poland to broaden its pipeline network, invest in gas links with neighbouring countries and build its first liquefied natural gas (LNG) terminal at the Baltic coast, which launched last month.

(Reporting by Adrian Krajewski; Editing by Mark Potter)

Stocks treated in this article : PGNiG SA, Gazprom PAO