Ukrainian President Volodymyr Zelensky addresses the Danish people from the steps of Christiansborg palace, the seat of Danish Parliament, in Copenhagen, Denmark, on Monday. Thousands of people had gathered in the palace courtyard to hear his speech, many waving Ukrainian or Danish flags. Claus Bech/Ritzau Scanpix via Associated Press

COPENHAGEN, Denmark — Ukrainian President Volodymyr Zelensky thanked Danish lawmakers Monday for helping his country resist Russia’s invasion, a day after Denmark and the Netherlands announced they will provide Kyiv with F-16 warplanes that could be delivered around the end of the year.

Zelensky told the lawmakers during a visit to Copenhagen that if Russia’s invasion is successful, other parts of Europe would be at risk from the Kremlin’s military aggression.

“All of Russia’s neighbors are under threat if Ukraine does not prevail,” he said in a speech before heading to Greece, the fourth European country he is visiting in three days, for talks with the government.

Zelensky says Ukraine is defending Western values of freedom and democracy against tyranny. He has argued that Ukraine needs to be properly provisioned to fend off Russia’s much bigger force.

Ukraine has been pressing its Western allies for months to give it American-made F-16s. Its armed forces are still using aging Soviet-era combat planes from the 1970s and ’80s, and its counteroffensive against Russian positions is advancing without air support, which analysts say is a major handicap.

In downtown Kyiv on Monday, people welcomed the news about F-16s though they also expressed frustration that the decision hadn’t been taken sooner.

“Finally,” said 33-year-old Larysa Shymko, who is from a Russia-occupied rea of the southern Kherson region. “I think every Ukrainian has been waiting for this for a long time.”

Yurii Lymar, a 38-year-old lawyer, said Ukraine’s Western allies “could approve such decisions a little faster, because every day in this … war means lots of Ukrainian people dying.”

Zelensky said on Telegram that Ukraine would get 42 jets. Denmark pledged 19 F-16s, which could be delivered around the end of the year when pilot training lasting four to six months is completed.

However, getting Ukrainian squadrons battle-ready could take much longer.

U.S. Air Force Gen. James Hecker, commander of U.S. air forces in Europe and Africa, said last week that he did not expect the F-16s to be a game-changer for Ukraine. Getting F-16 squadrons ready for battle could take “four or five years,” he said.

While some training has already begun for Ukrainian pilots, Dutch Prime Minister Mark Rutte said Sunday it’s just language lessons so far.

Training Ukrainian pilots is just one of the challenges in the anticipated deployment of F-16s. Questions also remain over who will carry out crucial aircraft maintenance, the supply of spare parts, runway maintenance and protective shelters for the planes on the ground, and what weapons the West will supply to arm the fighter jets.

Ukrainian air force spokesman Yuriy Ihnat said the F-16s will help Ukraine “change the course of events” in the war.

“Air superiority is the key to success on the ground,” he said in televised remarks.

Denmark rolled out the red carpet for Zelensky’s trip to Copenhagen. The Ukrainian leader also met at the Christiansborg Palace, the building housing the Danish parliament, with Denmark’s 83-year-old figurehead monarch, Queen Margrethe, who returned from vacation for the occasion.

Afterward, he spoke from the parliament steps to thousands of cheering people who waved Danish and Ukrainian flags in the palace’s courtyard.

The United States last week announced its approval for the Netherlands and Denmark to deliver the F-16s. That is needed because the aircraft are made in the United States.

On Sunday, Zelensky visited the Netherlands and inspected two gray F-16s parked in a hangar at a Dutch base in the southern city of Eindhoven together with Rutte.

He also visited an air base in southern Denmark where Ukrainian pilots will receive training on F-16s.

Rutte didn’t provide a number or timeframe for deliveries, saying it depends on how soon Ukrainian crews and infrastructure are ready.

Zelensky started his trip Saturday in Sweden, where he asked Prime Minister Ulf Kristersson for Swedish Gripen fighter jets. Sweden has said it will allow Ukrainian pilots to test the planes but has not made any commitments to hand them over.

On Monday, Russian air defenses jammed a Ukrainian drone west of Moscow and shot down another one on the outskirts of the city, Russia’s Defense Ministry said.

Two people were injured and one of them was hospitalized when drone fragments fell on a private house, Andrei Vorobyov, the governor of the Moscow region, said.

Such drone attacks have become an almost daily occurrence in Russia in recent weeks.

Also, Russian rail officials said that a relay cabinet used to run train traffic was set ablaze on the outskirts of Moscow, causing delays, according to the state RIA Novosti news agency.

Russian authorities have reported multiple similar incidents across the country, some of which have been blamed on acts of sabotage encouraged by Ukrainian security agencies.

In Ukraine, at least four civilians were killed and 25 others wounded by the latest Russian attacks, according to the Ukrainian presidential office.

Karl Ritter in Stockholm and Yuras Karmanau in Tallinn, Estonia, contributed to this report.