At least 21 people were killed and 48 injured by shelling in the Kherson region on Wednesday, Ukrainian officials said, as the death toll continues to rise.

A railway station and market in the city of Kherson were hit in strikes, which occurred across the Kherson region in southern Ukraine, officials said.

"A railway station and a crossing, a house, a hardware store, a grocery supermarket, a gas station -- do you know what unites these places? The bloody trail that [Russia] leaves with its shells, killing civilians in Kherson and Kherson region," Ukrainian President Volodymyr Zelenskyy said on Twitter.

All the victims were civilians, Zelenskyy said.

An ambulance was also damaged in the strikes, according to Ukrainian Prosecutor General Andriy Kostin.

"No military objects here. Just civilians, including children," Kostin said on Twitter.

At least one person was killed and three injured in the strike on the railway station, officials previously said.

The Biden administration has announced a new $300 million military aid package for Ukraine.

The package includes additional ammunition for U.S.-provided High Mobility Artillery Rocket Systems, as well as "additional howitzers, artillery and mortar rounds, and anti-armor capabilities that Ukraine is using to push back against Russia’s unprovoked war of aggression," the Department of Defense said in a statement.

This marks the Biden administration’s 37th drawdown of equipment from Defense Department inventories for Ukraine since August 2021.

Ukrainian President Volodymyr Zelenskyy rejected Russia's claim that his country was involved in the drone attack on the Kremlin early Wednesday.

Zelenskyy, who is currently in Finland, said the claim was the prelude to a "large-scale terrorist attack" from Russia.

"First of all, Ukraine wages an exclusively defensive war and does not attack targets on the territory of the Russian Federation," Zelenskyy said in a statement. "What for? This does not solve any military issue. But it gives RF grounds to justify its attacks on civilians."

Zelenskyy went on to say that various attacks in Russia could be the result of "guerrilla activities of local resistance forces."

Russian President Vladimir Putin's spokesman has accused Ukraine of trying to strike Putin's residence in the Kremlin with two drones overnight, but said they were brought down before they could reach their target.

No injuries were reported, Kremlin officials said. Putin was not at the residence at the time, they said.

Videos released on official social media channels appeared to show a drone strike the roof of the Senate Palace at the Kremlin.

The Kremlin said that "the Russian side reserves the right to retaliate whenever and wherever it deems necessary."

-ABC News' Patrick Reevell and Tanya Stukalova

Ukrainian Defense Minister Oleksiy Reznikov denied Ukraine was involved in the bombing of the Nord Stream pipeline, which carries natural gas from Russia to Germany. While the pipeline was not active at the time of the bombing last September, it was filled with fuel.

The denial comes after The New York Times reported that intelligence reviewed by U.S. officials suggests a pro-Ukrainian group carried out the Nord Stream bombings last year.

After the story broke, German Defense Minister Boris Pistorius warned against “jumping to conclusions” about who carried out the explosion, suggesting it could have been a “false flag” operation to blame Ukraine.

German authorities were reportedly able to identify the boat used for the sabotage operation, saying a group of five men and one woman using forged passports rented a yacht from a Poland-based company owned by Ukrainian citizens. The nationalities of the perpetrators are unclear, according to a separate report by Germany’s ARD broadcaster and Zeit newspaper.

“We have to make a clear distinction whether it was a Ukrainian group, whether it may have happened at Ukrainian orders, or a pro-Ukrainian group [acting] without knowledge of the government. But I am warning against jumping to conclusions,” Pistorius said on the sidelines of a summit in Stockholm.

A Russian diplomat said Russia has no faith in the U.S.‘s “impartiality” in the conclusions made from intelligence.

-ABC News’ Ellie Kaufman