KYIV, UKRAINE -- Ukraine said its forces shot down Russian drones and cruise missiles targeting the Black Sea port of Odesa before dawn Tuesday in what Moscow called "retribution" for an attack that damaged a crucial bridge to the Crimean Peninsula.

The Russians first sought to wear down Ukraine's air defences by firing 25 exploding drones and then targeted Odesa with six Kalibr cruise missiles, the Ukrainian military's Southern Command said.

All six missiles and the drones were shot down by air defences in the Odesa region and other areas in the south, officials said, though their debris and shock waves damaged some port facilities and a few residential buildings and injured an elderly man at his home.

The Russian Defence Ministry said its "strike of retribution" was carried out with sea-launched precision weapons on Ukrainian military facilities near Odesa and Mykolaiv, a coastal city about 50 kilometres (30 miles) to the northeast.

It destroyed facilities preparing "terror attacks" against Russia involving maritime drones, including a facility at a shipyard that was producing them, the ministry said. It added that it also struck Ukrainian fuel depots near the two cities.

It was not possible to verify the conflicting claims by both countries.

President Vladimir Putin blamed Ukraine on Monday for striking the Kerch Bridge, which links Russia with Crimea and was attacked in October 2022 and needed months of repairs. The bridge is a key supply route for the peninsula, which was illegally annexed by Moscow in 2014.

Ukrainian officials stopped short of directly taking responsibility, as they have done in similar strikes before, but Ukraine's top security agency appeared tacitly to admit to a role.

Satellite images taken Monday by Maxar Technologies showed serious damage to both eastbound and westbound lanes of the bridge across the Kerch Strait on the part nearest to the Russian mainland, with at least one section collapsed. The railroad bridge that runs parallel to the highway appeared undamaged.

The Russian military has sporadically hit Odesa and the neighbouring region throughout the war, but Tuesday's barrage was one of the biggest attacks on the area.

Ukrainian forces have been targeting Crimea with drones and other attacks. Kyiv has vowed to reclaim it from Russian control, arguing that the peninsula plays a key role in sustaining the Russian invasion and is a legitimate target.

The onslaught also came a day after Russia broke off a deal that had allowed Ukraine to ship vital grain supplies from Odesa during the war. Moscow said the decision was in the works long before the bridge attack.

Even so, Kremlin spokesman Dmitry Peskov alleged, without offering evidence, that the specific shipping lanes and routes used for the grain transport under the deal were abused by Ukraine.

"Our military has repeatedly said that Ukraine has used these grain corridors for military purposes," Peskov told reporters.

Ukrainian President Volodymyr Zelenskyy has said Ukraine will continue implementing the grain deal. Peskov warned that such action was risky because the region lies next to an area where there is fighting.

"If they try to do something without Russia, these risks must be taken into account," Peskov told reporters.

Zelenskyy said grain exports by sea and port security topped his meeting Tuesday with senior military commanders and government officials, adding that he received reports on logistics and protection of the coastal regions.

Andriy Yermak, the head of Ukraine's presidential office, said Russia is endangering the lives of millions around the world who need Ukrainian grain exports. Hunger is a growing threat in Africa, the Middle East and Asia, and high food prices have pushed more people into poverty.

"The world must realize that the goal of the Russian Federation is hunger and killing people," Yermak said. "They need waves of refugees. They want to weaken the West with this."

The United Nations and Ukraine's western allies slammed Moscow for halting the Black Sea Grain Initiative.

At the UN, Ukrainian Foreign Minister Dmytro Kuleba said "very active discussions" continue with the world body and other countries and entities on how to keep grain flowing, but a key issue is what would occur if Russia attacked a Ukrainian grain shipment.

Asked whether there was any talk of an international force or deployment to protect shipments, he told reporters that, "Everyone is looking for the way out, and every option is on the table."

Earlier, he urged countries at a General Assembly meeting to demand that Russia return to the deal "and stop its hunger games."

USAID is giving Ukraine a further US$250 million to support its agricultural sector as its chief, Samantha Power, visited Odesa and chided Moscow for its stance.

"Russia's disruption of maritime commerce since the beginning of its full-scale invasion, including blockading ports, delaying ship inspections, and, most recently, withdrawing from the Black Sea Grain Initiative, has severely choked the amount of grain Ukraine is able to provide to the world amid a global food crisis," a USAID statement said.

The Kremlin said the agreement would be suspended until Moscow's demands to lift restrictions on exports of Russian food and fertilizer to the world are met. Peskov reaffirmed an earlier Kremlin pledge to provide especially poor countries in Africa with grain for free, adding that the issue will be discussed at a Russia-Africa summit in St. Petersburg next week.

Meanwhile, the Russian Defence Ministry also said its forces had foiled a Ukrainian attack on Crimea using 28 drones.

The ministry said 17 of the attacking drones were shot down and 11 others were jammed electronically and crashed, with no damage or casualties.

Also Tuesday, satellite photos from Planet Labs PBC analyzed by The Associated Press showed that a convoy of vehicles arrived at a once-abandoned military base in Belarus, which was offered to Russia's private military contractor, Wagner. That followed a short-lived rebellion last month against the Russian Defence Ministry by Wagner's chief, Yevgeny Prigozhin.

The photos, taken Monday, show a long line of vehicles coming off a highway into the base near the Belarusian town of Osipovichi, some 75 kilometres (45 miles) northwest of the capital, Minsk.

Belaruski Hajun, an activist group that monitors troops movements in Belarus, said several convoys with Wagner fighters have entered the country since last week, including at least 170 vehicles on Tuesday. It estimated that about 2,500 Wagner mercenaries are now in Belarus.

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Associated Press writers Jon Gambrell in Dubai, United Arab Emirates, and Jennifer Peltz at the United Nations contributed.