Russian President Vladimir Putin on Thursday rejected claims that Moscow is responsible for the looming global food crisis brought on by the conflict in Ukraine.

Ukraine, a major exporter of grain, especially corn and wheat, has seen its production blocked by Moscow's military offensive, sparking a surge in prices and fears of food shortages that will particularly affect the poorest countries.

"We have not put any restrictions on the export of fertilizers, nor on the export of food products," Putin said as he welcomed Indonesian leader Joko Widodo, whose country holds the G-20 presidency, to the Kremlin.

Moscow does "not hinder the export of Ukrainian wheat," Putin said, adding that Russia is "in constant contact" with the United Nations agency in charge of the issue.

Putin instead blamed Western sanctions imposed on Russia. He said that by targeting the owners of fertilizer companies, Western sanctions have "created conditions that made it much more difficult" to deliver certain products internationally.

Moscow says it would allow Ukrainian ships loaded with food products to leave if the Ukrainian military demined its ports, an option rejected by Kyiv, which fears for the safety of its Black Sea coast.

For its part, Russia, another grain-producing power, cannot sell its crops and fertilizers because of Western sanctions affecting the financial and logistics sectors.

The Kremlin announced this week that it had "responded positively" to the invitation to the G-20 summit to be held in Bali, Indonesia, in November, suggesting that Putin would attend in person.

Italian Prime Minister Mario Draghi, however, said after a G-7 summit where Widodo was invited, that Indonesia had ruled out Putin's presence, a statement the Kremlin has rejected.

The terms of Russian participation will be determined after "an analysis of the situation," Kremlin spokesperson Dmitry Peskov said Thursday.

Western countries, led by the United States, are putting pressure on Indonesia to exclude Russia from the meeting, to which Ukraine has also been invited as a guest country.

Widodo visited Ukraine on Wednesday.