Russia's defense ministry said on Sunday its forces had launched a wave of missile strikes against Ukrainian military and infrastructure sites the previous day.
An ammunition explosion caused by "careless" handling of a grenade in Russia's Belgorod region on the border with Ukraine killed three people and injured 15, Russian news agencies reported on Sunday.
The blast occurred in a cultural center repurposed for Russia's armed forces to store ammunition, state news agencies reported, citing local emergency services for the toll.
Belgorod region borders Ukraine and is the location of several Russian military bases and training grounds.
The 112 and Baza Telegram channels, linked to Russia's law enforcement agencies, said the dead and injured were conscripts called up to fight in Ukraine under a mobilization drive.
They reported that the blast occurred after a senior soldier mishandled a grenade in front of subordinates, accidentally detonating it. TASS said "careless handling of ammunition" caused the explosion.
Reports did not say when the incident took place.
Belgorod borders the northeast of Ukraine, just across from the city of Kharkiv, which has been targeted by multiple Russian missile attacks since the invasion of Ukraine last February.
The ministry did not mention the city of Dnipro as a specific target of the strikes. Thirty people have been confirmed dead so far in destroyed Dnipro apartment block, according to the regional governor's adviser, Natalia Babachenko. Between 30 to 40 people could still be trapped under debris, she said.
"On 14 January 2023, a missile strike was launched against Ukraine's military command and control system and energy facilities," the defense ministry said in a statement.
"All designated targets were hit. The objective of the strike has been achieved," it added.
"On 14 January 2023, a missile strike was launched against Ukraine's military command and control system and energy facilities, all designated targets were hit. The objective of the strike has been achieved,"
Russian Defense Ministry
The Russian strategy in furthering the invasion of Ukraine.
Russia also said its troops had made progress towards the city of Bakhmut in Ukraine's Donetsk region, which has been the focus of Russian attacks for months. It said its troops had advanced towards the northern outskirts of the city.
Russia reported its first major territorial gain in months last week, when it said its troops captured the town of Soledar, just a few kilometers north of Bakhmut, after months of brutal fighting for the small town.
Ukraine has rejected Russia's claims to have taken Soledar and insisted on Saturday that its forces were battling to hold it, but officials acknowledged the situation was difficult, with street fighting raging and Russian forces advancing from various directions.
Russian President Vladimir Putin heralded Russia's latest battlefield gains in remarks on Sunday.
Russia last week announced the latest shake-up to its military command, putting Valery Gerasimov, Chief of the General Staff, in day-to-day charge of the military campaign.
Saturday's missile strikes - the largest Russian attacks so far in 2023 - suggest Russia will continue with its strategy of attempting to target Ukraine's energy and infrastructure networks.