Russian air defenses downed 389 incoming Ukrainian drones, Russia’s Defense Ministry said Wednesday, in what was the largest reported overnight attack on Russian regions and Crimea since Moscow’s forces invaded Ukraine more than four years ago.

The drones were stopped over 13 Russian regions as well as the Crimean Peninsula, which Russia illegally annexed from Ukraine in 2014.

The attack underlined the growing capability of Ukraine’s domestically developed and manufactured long-range drones.

It came a day after Russia fired almost 1,000 drones and 34 missiles at civilian areas of Ukraine in the space of 24 hours, extending its usual nighttime barrage into daylight hours in one of its biggest aerial attacks of the war. At least six people were killed and around 50 people were injured, Ukrainian authorities said.

AP AUDIO: Russia says it shot down almost 400 Ukrainian drones as Moscow and Kyiv escalate aerial barrages

AP correspondent Ben Thomas reports there are signs Russia’s spring offensive in Ukraine has begun.

The United Nations cultural organization UNESCO on Wednesday said it was “deeply alarmed” by Russia hitting a World Heritage site in the western Ukraine city of Lviv during that bombardment.

The escalation in aerial attacks comes amid a pause in U.S.-mediated talks between delegations from Moscow and Kyiv, as Washington’s attention is diverted by the Iran war and as Ukraine anticipates a spring offensive by Russia’s bigger army.

Alexander Drozdenko, governor of the Leningrad region north of Moscow, said 56 drones were shot down there, and a fire broke out in the Baltic Sea port of Ust-Luga as the result of Ukraine’s attack.

Ukrainian forces also carried out a missile strike on the Belgorod region on the border with Ukraine overnight, damaging energy infrastructure, its Gov. Vyacheslav Gladkov said. Power, water and heating supplies were disrupted, he said.

The Ukrainian drone blitz caught public attention in the Baltic states, which lie northwest of Ukraine and relatively close to potential Russian targets in the Leningrad region, which includes St. Petersburg, where drones came down.

Officials in Estonia, Latvia and Lithuania, which have been close allies of Ukraine in the war, said the drones likely didn’t target them.

Estonian media reported that a drone coming from Russia clipped a power plant’s chimney early Wednesday but said electricity production was not disrupted. The plant is around 50 kilometers (31 miles) from the port of Ust-Luga that Ukraine targeted.

Also Wednesday, the Latvian defense ministry said a drone had crashed in a region close to Russia. No injuries or damage were reported.

Lithuanian officials said a stray Ukrainian drone crashed into a frozen lake near the Belarusian border on Monday.

In Moldova, on Ukraine’s southwest border, authorities on Tuesday urged citizens to spare electrical energy during peak hours, after Russian strikes on Ukraine’s energy grid cut a key power line between Moldova and Romania.

___

Associated Press writers Illia Novikov in Kyiv, Ukraine and Kirsten Grieshaber in Berlin contributed to this story.

___

Follow AP’s coverage of the war in Ukraine at https://apnews.com/hub/russia-ukraine