A three-day ceasefire declared by Russia came into effect on Thursday morning with skies over Ukraine’s major cities quiet, in a change from successive nights of heavy attacks by Russian drones and ballistic missiles.

Ukraine’s air force reported that after the start of the Kremlin-sponsored ceasefire Russian aircraft twice launched guided bombs on the Sumy region of northern Ukraine. There was no word on damage and Reuters could not independently verify the attacks.

The Russian ceasefire, coinciding with the 80th anniversary of the World War Two defeat of Nazi Germany, went into effect at midnight Moscow time (2100 GMT).

As part of the anniversary events, Russian President Vladimir Putin is hosting Chinese President Xi Jinping and other leaders in Moscow, and will review a military parade on Moscow’s Red Square on May 9.

Ukraine has not committed to abide by the Kremlin’s ceasefire, calling it a ruse by Putin to create the impression he wants to end the war, which began when Russia launched a full-scale invasion of Ukraine in February 2022. Putin says he is committed to achieving peace.

Ukraine launched successive drone attacks on Moscow this week, which had forced the closure of airports in the Russian capital and the grounding of airliners.

Apart from the Ukrainian air force reports about the two launches of guided bombs, there were no reports in Ukraine of any Russian long-range drones or missiles being launched on Ukrainian cities early on Thursday.

As of 3:45 am (00:45 GMT), the capital Kyiv was quiet, in contrast to 24 hours earlier when the city had reverberated with the sound of explosions from waves of Russian airborne attacks, and outgoing Ukrainian anti-aircraft fire.

It was not immediately clear if there was a pause in fighting on the frontlines between Russian and Ukrainian forces. A Reuters witness near the front in eastern Ukraine said early on Thursday he could hear no sounds of fighting.

Ukraine’s President Volodymyr Zelenskiy said on Wednesday that his country stood by its offer to observe a 30-day ceasefire in the war with Russia.

“We are not withdrawing this proposal, which could give diplomacy a chance,” Zelenskiy said in his nightly video address.

Russia, he said, had made no response to the 30-day offer except for new strikes.

“This clearly and obviously demonstrates to everyone who the source of the war is,” the Ukrainian president added.

Zelenskiy also appeared to acknowledge the numerous drone attacks that have been targeting Russian sites, including the city of Moscow, as the World War Two commemorations approached.

“It is absolutely fair that Russian skies, the skies of the aggressor, are also not calm today, in a mirror-like way,” he said on Wednesday.

Moscow Mayor Sergei Sobyanin, in a series of posts on the Telegram messaging app over a five-hour period, said 14 drones headed for the capital had been repelled or destroyed. This happened before the Kremlin-sponsored three-day ceasefire took effect.

The US proposed the 30-day ceasefire in March and Ukraine agreed. Russia has said such a measure could only be introduced after mechanisms to enforce and uphold it are put in place.

Both countries are under pressure from US President Donald Trump to bring a swift end to the war, the biggest conflict in Europe since World War Two.

Russian Foreign Ministry spokeswoman Maria Zakharova expressed surprise at remarks from US envoy Keith Kellogg that Putin may be obstructing a comprehensive ceasefire.

“The only obstacle to the ceasefire is Kyiv, which violates agreements and is unwilling to seriously discuss the terms of a long-term ceasefire,” Zakharova said.