The Russian capital was targeted by an alleged drone attack early Monday while Moscow launched a series of new strikes on a key port in southern Ukraine.
Russian authorities accused Kyiv of launching the attack that saw one of the drones fall near the Defense Ministry's main headquarters.
Moscow Mayor Sergei Sobyanin said there were no casualties when the drones struck two nonresidential buildings. The Defense Ministry claimed that the military jammed both attacking drones, forcing them to crash.
Russian media reported that one of the drones fell on the Komsomolsky highway near Moscow's center, close to the main Defense Ministry building. Another drone hit an office building in southern Moscow, gutting its upper floors.
Ukrainian authorities didn't immediately claim responsibility for the strike, which was the second drone attack on the Russian capital this month.
In the previous attack on July 4, the Russian military said four of the five drones were downed by air defenses on the outskirts of Moscow and the fifth was jammed by electronic warfare means and forced down.
The raid prompted authorities to temporarily restrict flights at Moscow's Vnukovo airport and divert flights to two other Moscow airports.
Russian authorities said that another Ukrainian drone attack early Monday struck an ammunition depot in Crimea and forced a halt in traffic on a major highway and a railway crossing the Black Sea peninsula that was illegally annexed by Moscow in 2014.
The Moscow-appointed head of Crimea, Sergei Aksyonov, said the authorities also ordered the evacuation of several villages within a 5-kilometer (3-mile) radius of the depot that was hit.
Aksyonov said the military shot down or jammed 11 attacking drones.
On Saturday, a similar drone attack on Crimea hit another ammunition depot, sending huge plumes of black smoke skyward and also forcing the evacuation of residents.
Russian forces, meanwhile, struck port infrastructure on the Danube River in southern Ukraine with exploding drones early Monday, injuring four workers and destroying a grain hangar and storage for other cargo, the Ukrainian military said. It said that Ukrainian forces downed three of the attacking drones.
The strike was the latest in a barrage of attacks that has damaged critical port infrastructure in southern Ukraine in the past week. The Kremlin has described the strikes as retribution for last week's Ukrainian strike on the crucial Kerch Bridge linking Russia with Crimea.
Speaking at the Aspen Security Forum via video link over the weekend, Ukrainian President Volodymyr Zelenskyy called the bridge a legitimate target for Ukraine, noting that Russia has used it to ferry military supplies and it must be "neutralized."
Since Moscow canceled a landmark grain deal a week ago amid Kyiv's grinding efforts to retake its occupied territories, Russia has launched repeated attacks on Odessa, a key hub for exporting grain.
On Sunday, at least one person was killed and 22 others wounded in an attack on Odessa that severely damaged 25 landmarks across the city, including the Transfiguration Cathedral.
UNESCO strongly condemned the attack on the cathedral and other heritage sites and said it will send a mission in the coming days to assess damages.
Odessa's historic center was declared a UNESCO World Heritage site earlier this year, and the agency said the Russian attacks contradict Moscow's pledge to take precautions to spare World Heritage sites in Ukraine.
The Russian military denied that it targeted the Transfiguration Cathedral, claiming without offering evidence that it was likely struck by a Ukrainian air defense missile.
