Joanna Kakissis

Ukraine's air force says Russia used 480 drones and 29 missiles in the attacks.

Kharkiv, Ukraine's second largest city, was the hardest hit.

A ballistic missile struck a high-rise building in the northeastern city, killing several residents and injuring many more.

Russia frequently launches airstrikes on Ukraine.

Ukrainian forces have learned how to shoot down attack drones like Shaheds, which were designed in Iran.

Ukraine is now sharing that expertise with Gulf nations.

Iranian forces have attacked U.S.

sites in these nations with Shahed drones in retaliation for the war that the U.S.

and Israel is waging on Iran.

Joanna Kakissis, NPR News, Kyiv.

In a video address, Zelensky talked about the Iranian leadership's close ties with Russian President Vladimir Putin and how, during four years of all-out war, Russia has struck Ukrainian cities more than 57,000 times with Iranian-designed Shahed drones.

The Iranian regime chose to be an accomplice to Putin and supplies him with Shahids, Zelensky said, not only with the drones, but with the technology to make them.

Shahids resemble small airplanes and often carry explosives.

The drones buzz like mopeds when they fly into Ukrainian cities, often tearing into apartment buildings.

Russia now produces thousands of these drones every month using Iranian blueprints.

Joanna Kakissis, NPR News, Kyiv.

Speaking to reporters during a private briefing in Kyiv, Zelensky said it was impossible for him to travel to Moscow, adding that it would be just as plausible as Putin coming to Kyiv.

I'm openly inviting him, Zelensky said, if he dares.

Zelensky explained that he's open to meeting Putin on neutral ground.

Zelensky also welcomed President Trump's claim that Putin has promised to stop strikes on Ukraine's energy grid, which has left thousands without power in sub-zero temperatures.