"It is obvious that there are no grounds for the further continuation of the Black Sea Initiative which expires on July 17," Russia's foreign ministry said.
"The normalisation of Russian supplies of food and fertilisers to world markets - provided for by the Russia-U.N. Memorandum - has continued to degrade," the ministry also stated.
Moscow says the problems stem from secondary effects of Western penalties on shipping and insurance companies as well as banks.
Moscow has also accused Ukraine of destroying a section of a pipeline Russia used to export ammonia, a core component of fertilizer.
The foreign ministry also said that most of the Ukrainian exports were going to wealthy countries, contradicting data provided by the U.N. and Ukraine.
The conflict between Russia and Ukraine - both major grain exporters - triggered fears of a global food crisis when major Ukrainian ports were blocked by Moscow's warships.
In July 2022, the agreement allowing Ukrainian grain exports to restart was signed, as well as a parallel memorandum on unhindered Russian food and fertilizer exports.
Ukrainian Infrastructure Minister Oleksandr Kubrakov has said that 29 ships with 1.4 million tons of grain are blocked because of delayed inspections, blaming Russia for the holdup.
Kubrakov also wrote on Twitter that Russia had stopped the registration of inbound ships since June 26.
Moscow said in its statement Tuesday that it would ensure the back-log of ships awaiting inspection would be clear before the deal expires on July 17.
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