Nato said on Wednesday it was stepping up surveillance of the Black Sea region as it condemned Russia's exit from a deal assuring the safe passage of ships carrying Ukrainian grain.
The announcement came after a meeting of the Nato-Ukraine Council, a body established earlier this month to coordinate cooperation between the Western military alliance and Kyiv.
"Allies and Ukraine strongly condemned Russia’s decision to withdraw from the Black Sea grain deal and its deliberate attempts to stop Ukraine’s agricultural exports on which hundreds of millions of people worldwide depend," Nato said in a statement.
"Nato and Allies are stepping up surveillance and reconnaissance in the Black Sea region, including with maritime patrol aircraft and drones," the statement said.
The deal that has allowed the safe Black Sea export of Ukraine's grain for the past year expired on July 17 after Russia quit in a move the UN said would "strike a blow to people in need everywhere."
Moscow suggested it would consider reviving the deal if demands to improve exports of its own grain and fertiliser were met.
The Nato statement criticised a Russian warning that parts of the Black Sea's international waters were temporarily unsafe for navigation.
As part of that warning, Russia also declared that any ships travelling to Ukraine's Black Sea ports would be seen as possibly carrying military cargoes.
"Allies noted that Russia’s new warning area in the Black Sea, within Bulgaria’s exclusive economic zone, has created new risks for miscalculation and escalation, as well as serious impediments to freedom of navigation," the Nato statement said.
Bulgaria is a member of Nato.
Nato also said it condemned recent Russian attacks on Odesa, Mykolaiv and other port cities, including a drone strike on a Ukrainian grain storage facility in the Danube port city of Reni, near the border with Nato-member Romania.
"We remain ready to defend every inch of Allied territory from any aggression,” Nato Secretary General Jens Stoltenberg said.