EINDHOVEN, Netherlands (AP) — The Netherlands and Denmark announced Sunday they will give F-16 warplanes to Ukraine, a long-awaited announcement that Ukrainian President Volodymyr Zelenskyy called an important motivation for his country’s forces, embroiled in a difficult counteroffensive against Russia.

The promise of new fighter jets came the day after an unusually brazen Russian missile strike on a Ukrainian theater that killed seven people and wounded almost 150 others in the northern city of Chernihiv. Zelenskyy vowed stern retaliation for the attack, whose victims included a slain 6-year-old girl dead and 15 wounded children.

Ukrainian President Volodymyr Zelenskyy, left and Denmark’s Prime Minister Mette Frederiksen hold a press conference, at Skrydstrup Airbase, in Vojens, Denmark, Sunday, Aug. 20, 2023. Denmark’s prime minister says it will donate 19 F-16 fighter jets to Ukraine. It follows a similar offer earlier from the Netherlands Ukrainian President Volodymyr Zelenskyy called an important motivation for his country’s forces, who are embroiled in a difficult counteroffensive against Russia.

After months of entreaties from Zelenskyy for F-16s to bolster the Ukrainian air force, the U.S. recently gave approval for the Netherlands and Denmark to provide Ukraine the American-made jets. Zelenskyy travelled to both countries Sunday to finalize the delivery deals.

”F-16s will certainly give new energy, confidence, and motivation to fighters and civilians. I’m sure it will deliver new results for Ukraine and the entire Europe,? the Ukrainian leader said.

Ukraine hopes the jets will give it a combat edge, after launching a counteroffensive against the Kremlin’s forces without air cover from Western aircraft, placing its troops at the mercy of Russian aviation and artillery.

Danish Prime Minister Mette Frederiksen pledged 19 F-16s to Ukraine and said she hoped the first six could be handed over around New Year. Dutch Prime Minister Mark Rutte didn’t provide a number or timeframe, saying it depends on how soon Ukrainian crews and infrastructure are ready. Zelenskyy said on his Telegram channel that Ukraine would get 42 jets.

“The F-16s will not help immediately now with the war effort. It is anyway a long-term commitment from the Netherlands,” Rutte said. “We want them to be active and operational as soon as possible. … Not for the next month, that’s impossible, but hopefully soon afterward.”

He and Zelenskyy inspected two gray F-16s parked in a hangar at a Dutch base in the southern city of Eindhoven.

Ukrainian President Volodymyr Zelenskyy, left, and Denmark’s Prime Minister Mette Frederiksen sit in a F-16 fighter jet at Skrydstrup Airbase, in Vojens, Denmark, Sunday, Aug. 20, 2023.

A few hours later, Zelenskyy and his wife were received by Frederiksen, other Danish Cabinet ministers and Crown Princess Mary at the Skrydstrup air base in southern Denmark where Ukrainian pilots will receive F-16 training in coming months. The two leaders climbed into a Danish F-16 and tried out the seats.

Frederiksen said “hopefully” six fighter jets could be delivered around New Year, eight more next year and the remaining five in 2025.

“Please take this donation as a token of Denmark’s unwavering support for your country’s fight for freedom,” she said.

Zelenskyy called the Dutch and Danish donations a “huge push for other countries who were in doubt” about providing Ukraine with F-16s. Asked whether there were conditions attached to the donations, such as a commitment not to use them in Russian territory, Zelenskyy said that had not been discussed but added that defending Ukrainian territory was the “main goal.”

The Dutch and Danish governments are also spearheading a coalition that is working to train Ukrainian pilots to fly the advanced fighter jets.