Dec 31 (Reuters) - Ukraine's gas transit operator said

Russia had not nominated any gas flows for Jan. 1 through the

Ukrainian pipeline to Europe as of 1500 GMT on Tuesday, hours

ahead of the expiration of a five-year contract between Gazprom

and Ukraine's Naftogaz.

Ukraine has repeatedly said it will not sign a new deal to

replace the one expiring on Dec. 31 due to Russia's full-scale

invasion of its territory, now approaching its third year.

2025 could prove to be the first year since the collapse of

the Soviet Union in 1991 when no gas will be transported through

Ukraine to Europe.