A deadly blast at a market has killed at least 25 people on the outskirts of Donetsk in Russian-occupied Ukraine.
A further 20 people, including two children, were injured in the strike in the suburb of Tekstilshchik.
The head of Russian-installed authorities in Donetsk, Denis Pushilin, has claimed the shells had been fired by the Ukrainian military.
His claims couldn't be independently verified and Kyiv has not commented on the event.
Mr Pushilin said the area had been hit by artillery, and the shells were fired from the direction of Kurakhove and Krasnohorivka to the west.
He also confirmed that emergency services continued to work at the scene.
In a statement, Russia's Ministry of Foreign Affairs described the strike, which it blamed on Ukraine, as a "terrorist attack."
"These terrorist attacks by the Kyiv regime clearly demonstrate its lack of political will towards achieving peace and the settlement of this conflict by diplomatic means," it said.
A fire also broke out at a chemical transport terminal at Russia's Ust-Luga port following two explosions on Sunday, regional officials said.
Local media reported that the port had been attacked by Ukrainian drones, causing a gas tank to explode.
The blaze was at a site run by Russia's second-largest natural gas producer, Novatek, 165 kilometres southwest of St. Petersburg.
In a press statement to Russian media outlet RBC, the company said that the fire was the result of an "external influence."
It also said that it had paused operations at the port.
Yuri Zapalatsky, the head of Russia's Kingisepp district, where the port is based, said in a statement that there were no casualties, but that the area had been placed on high alert.
The Russian Ministry of Defense did not report any drone activity in the Kingisepp area in its daily briefing. It said that four Ukrainian drones had been downed in Russia's Smolensk region, and that two more had been shot down in the Oryol and Tula regions.
Russian officials previously confirmed that a Ukrainian drone had been downed on the outskirts of St. Petersburg on Thursday.
Russian and Ukrainian forces have continued to fight from largely static positions along the roughly 1,500-kilometer (930-mile) front line throughout the winter.
Recent Russian attacks have tried to find gaps in Ukraine's defences by using large numbers of various types of missiles in an apparent effort to saturate air defence. systems.
The massive barrages — more than 500 drones and missiles were fired between December 29 and January 2, according to officials in Kyiv — are also using up Ukraine's weapons stockpiles.