The Kremlin said Monday that the Ukraine grain deal had "de facto ended" hours before it was due to expire, and that Moscow would return to the landmark agreement if its conditions were met.
The crucial deal, brokered by the UN and Turkey, is officially due to run out at the end of Monday. It allows Ukraine to export grain via the Black Sea.
Moscow has threatened to leave the deal for weeks, saying its side of the agreement was not properly implemented.
"The Black Sea agreements have de facto ended today," Kremlin spokesman Dmitry Peskov said.
"The grain deal has ceased. As soon as the Russian part (of the agreements) are fulfilled, the Russian side will immediately return to the grain deal."
After the Kremlin's announcement, Russian news agencies reported Moscow had notified Turkey, Ukraine and the UN that it was against extending the deal.
"Russia today officially notified the Turkish and Ukrainian sides, as well as the UN Secretariat of its objection to the extension of the deal," the TASS news agency quoted foreign ministry spokeswoman Maria Zakharova as saying.
The Kremlin's announcement that Moscow intended to leave the deal came hours after a Ukrainian attack on Russia's bridge to annexed Crimea killed two civilians.
But Peskov said Moscow letting the deal expire was not "linked" to the attack, saying President Vladimir Putin had long voiced his discontent with the agreements.
"Before this attack, the position was declared by President Putin."
Putin has repeatedly threatened to pull out of the agreement, arguing that elements of the deal allowing the export of Russian food and fertilisers had not been honoured.
Over the weekend, Putin also said the main objective of the deal -- the supply of grain to poorer countries -- had not been achieved.