"There are a lot of unanswered questions regarding our part of the deal ... now we have to make a decision," Kremlin spokesman Dmitry Peskov told reporters.
Russia has laid out a list of conditions for it to agree to an extension, including allowing the Russian Agricultural Bank (Rosselkhozbank) to reconnect to the Swift payment system.
Supplies of agricultural machinery, spare parts and services also have to be resumed, and obstacles to granting Russian vessels insurance and access to foreign ports must be lifted, it says.
Moscow's conditions also include the resumption of ammonia exports for fertilizers through a major pipeline that goes through 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.
Russia has however repeatedly threatened to withdraw from the deal, claiming that obstacles remain to its own food exports.
Moscow says the problems stem from secondary effects of Western penalties on shipping and insurance companies as well as banks.
During recent talks in Istanbul, Turkish Defense Minister Hulusi Akar said: "we are heading toward an agreement on the extension of the grain deal."
