Russia on Tuesday launched overnight attacks across multiple Ukrainian cities using hundreds of drones and a missile strike, damaging energy infrastructure and injuring at least 15 people.

Ukraine's Air Force reported that Russia had sent out 400 drones along with one ballistic missile, with the main targets being Kharkiv, Kryvyi Rih and Vinnytsia, which are spread across different regions of the country. Earlier, Ukrainian authorities had said that a drone strike had killed two people in the frontline city of Kupiansk.

President Volodymyr Zelenskyy wrote on Telegram that these extensive long-distance attacks were focused on damaging energy systems.

"We are now doing our best to restore everything in Kryvyi Rih, and power supply will be restored over the course of the day."

According to the Air Force, most of the drones were shot down, but 12 locations were still struck by 57 drones and a missile.

Russia rejected President Trump's "ultimatum" that called on Moscow to sign a ceasefire deal to end the Ukraine war within 50 days, calling it "unacceptable" and instead stressed the need for further talks while making clear that the invasion ordered by President Vladimir Putin would continue until its full goals are met.

Deputy Foreign Minister Sergey Ryabkov, responding to Trump’s warning of imposing 100 percent secondary tariffs on countries doing business with Russia if a deal is not signed in time, said that "any attempts to make demands, especially ultimatums, are unacceptable to us," as reported by Russia’s state agency TASS.

"We have to concentrate on political and diplomatic efforts. Repeatedly, the President of the Russian Federation has stated that we are prepared to negotiate and the diplomatic solution is more preferable for us," Ryabkov was cited as saying. "If we fail in what we are aiming for through diplomacy, then the SVO (war in Ukraine) will go on… This is an unbreakable stance. We would prefer Washington and NATO in general to treat it with the utmost seriousness."

Kremlin spokesman Dmitry Peskov separately described Trump’s announcement as "quite serious."

"Part of it is delivered directly to (Russian) President Putin. We certainly have time to work over what was stated in Washington," Peskov said during his daily briefing on Tuesday. "Whether and when President Putin finds it necessary, he will certainly respond to it. I do not want to anticipate, so let us wait for the decision by Putin whether to comment on it personally or not."

Russia’s former President Dmitry Medvedev, a key Kremlin figure, described Trump’s comments as "a theatrical ultimatum" on social media and added that "Russia didn't care."

On Tuesday, Mr. Trump said "at the end of 50 days, if we don't have a deal, too bad." He added that by then, "the tariffs are going to go, and other sanctions" but also said that Ukrainian President Volodymyr Zelensky "shouldn't target" Moscow.

Speaking on Monday from the Oval Office alongside NATO Secretary General Mark Rutte, Mr. Trump said "We are very unhappy, I am, with Russia." He also confirmed a new deal for the United States to produce more weapons for NATO allies who would then send those weapons to Ukraine.

"We're not going to buy it, but we'll make it, and they're going to be paying for it," said Mr. Trump.

"This is quite big," Rutte responded. "And the choice is that you want Ukraine to have what it should have to ensure, in order to be able to defend itself against Russia, but you want Europeans to pay for it, which is completely logical."

Mr. Trump repeated his criticism of President Putin, whom he had recently called "absolutely crazy" for ordering attacks on civilian areas in Ukraine. On Monday, he suggested that Putin often makes promises and then breaks them.

"I always hang up, say, 'Well, that was a nice phone call.' And then missiles are launched into Kyiv or some other city and I say, 'That's strange.'" Mr. Trump said. "After that happens three or four times, you say, the talk doesn't mean anything."

When asked during an interview with BBC News, which is a partner of CBS News, whether he had stopped trying to negotiate with Putin, Mr. Trump said "I'm disappointed in him, but I'm not done with him. But I'm disappointed in him."

In a post on social media on Monday, President Zelenskyy said that he had spoken with Mr. Trump and thanked him "for the readiness to assist Ukraine and to continue cooperation to end the killings and to build a lasting and just peace."

"It's good that we have such a close relationship, and that the countries of the Alliance are striving to raise defense spending," Zelenskyy said, adding that he and Mr. Trump had agreed to talk again soon.

"We agreed to talk more frequently over the phone and coordinate our actions in the future as well," he said. "Thank you, Mr. President! Thank you, America!"

Russia began its full-scale invasion of Ukraine on February 24, 2022, sending tens of thousands of troops and launching missile attacks following its earlier annexation of Crimea and support for separatist groups in the region.

Although Russia has continued to control Crimea and has set up its own rule in large parts of eastern Ukraine over the last three years, this control has not been recognized by the United States, the United Nations, or most of the world.

One of President Putin’s key conditions for a ceasefire is that Ukraine and its global supporters must accept Russia’s authority over at least some of the areas it currently occupies.