Explosions have rocked a key Ukrainian port just a day after Kyiv and Moscow reached a landmark deal to allow the resumption of grain exports.
Two missiles hit the port city of Odesa in the early hours of Saturday morning, Ukraine’s military said.
Blaming Russia, Ukraine’s air force chief said grain stores at the port were deliberately targeted.
Under the terms of Friday’s deal, Russia agreed not to target ports while grain shipments are in transit.
The UN had described the deal as “a beacon of hope” following months of conflict.
In a post to social media, the Ukrainian military’s southern command centre said two Kalibr missiles hit the port, while two more were shot down by air defence systems.
Oleksiy Honcharenko, a local MP, wrote on Telegram that the city’s port had caught fire after the strike.
“These scumbags sign contracts with one hand and direct missiles with the other,” Mr Honcharenko wrote.
“So, we need planes and we need to sink the entire Black Sea fleet of the Russian Federation. This will be the best arrangement for the export of grain.”
It is unclear whether there were casualties or substantial damage.
US Ambassador Bridget Brink called the attack “outrageous,” adding that Russia “must be held to account”.
On Friday, officials from Kyiv and Moscow signed a deal to allow millions of tonnes of grain trapped in Ukraine to be exported.
According to diplomats, among the agreements struck Russia agreed not target ports while shipments are in transit and Ukraine promised to guide cargo ships through mined waters.
The deal – which took two months to reach – is set to last for 120 days, with a co-ordination and monitoring centre to be established in Istanbul, staffed by UN, Turkish, Russian and Ukrainian officials. It can be renewed if both parties agree.
Andriy Yermak, the head of President Volodymyr Zelensky’s office, condemned the attack and accused Russia of “systematically creating a food crisis”.
“The Russian missile is Vladimir Putin’s spit in the face of UN Secretary General António Guterres and President of Turkey Recep Erdogan, who made enormous efforts to reach an agreement, and to whom Ukraine is grateful,” added Oleh Nikolenko, a spokesperson for Ukraine’s foreign ministry.
In fighting on the ground, British defence officials said Russian troops in the Kherson region risk being cut off from their supply lines by Ukrainian forces.
A large counteroffensive has been launched by Kyiv in the south of the country and its forces have used new long-range US supplied missile system to target the Antonovsky Bridge in Kherson.
If the bridge were to be destroyed, Russian supply lines would be severely stretched.