Russia-Ukraine updates: 2 US veterans who joined Ukrainian forces missing

After five weeks of relative calm in Kyiv, Russian rockets hit Ukraine's capital city on Sunday as Russian President Vladimir Putin warned of strikes on "new targets" if the United States goes through with plans to supply Ukraine with longer-range missiles.

Ukrainian Deputy Minister of Defense Hanna Maliar said the war is still in its "hot phase" and "capturing Kyiv is still Russia’s main goal."

An ABC News crew visited Kyiv's Darnytskyy district, where several Russian cruise missiles slammed into a railway repair plant. One building was still on fire when the ABC News crew arrived. Nearby, another missile strike left a creater on a cement path.

It took hours before Ukrainian authorities permitted media access to the site, saying the area needed to be cleared for safety first.

The Russians claimed the attack in Darnystskyy destroyed military vehicles and armaments. Ukrainian officials said the missiles hit a railway repair plant where no tanks were stored.

Speaking on Russian TV on Sunday, Putin issued a warning to the West on supplying the Ukrainians with high-powered rocket systems. He said if the West carried through with it, Russia would hit "new targets they had not attacked before."

President Vladimir Putin warned that Russian forces would strike new targets if the West began supplying Ukraine with longer-range missiles.

"But if they [missiles] are actually delivered, we will draw appropriate conclusions and apply our own weapons, which we have in sufficient quantities to carry out strikes on targets we aren't striking yet," Putin told Rossyia 1 TV Channel in an interview on Sunday.

-ABC News’ Tanya Stukalova and Tomek Rolski

Two Reuters journalists were injured and their driver killed in an attack in eastern Ukraine Friday, Reuters said.

Photographer Alexander Ermochenko and cameraman Pavel Klimov were traveling into Sievierodonetsk when they came under fire on a Russian-held part of the road, according to Reuters. Klimov was treated for an arm fracture and Ermochenko for a small shrapnel wound at a nearby hospital.

Their driver, who has not been identified, had been assigned to Reuters by Russia-backed forces.

"Reuters extends its deepest sympathies to the family of the driver for their loss," a Reuters spokesperson said in a statement.

Ukrainian President Volodymyr Zelenskyy marked the 100th day of the war by posting a video of himself outside his office in Kyiv with his defense minister, prime minister and parliamentary leader.

"Our team is much bigger. The Armed Forces of Ukraine are here. The most important thing is our people, the people of our state are here," Zelenskyy said. "We have been defending Ukraine for 100 days. Victory will be ours."

The video was notably shot in the same location with the same people as one posted after the first day of the Russian invasion, on the evening of Feb. 25. "We are here," Zelenskyy said in that video.

-ABC News' Kerem Inal and Max Uzol