Ukrainian authorities were working to extract people from the rubble of a multistory residential building in the country’s east, which Ukrainian officials described as one of a series of civilian sites hit by Russian missiles or long-range artillery in recent days.

According to Ukraine’s emergency services, the death toll from the Russian missile attack on the five-story structure in Chasiv Yar, Donetsk region, has risen to 19 people. As of Monday morning, eight people had been pulled from the rubble.

Artillery battles and airstrikes have remained intense, particularly near the front lines in eastern Ukraine, even as some analysts believe Russia has paused its ground forces’ advance. According to Mr. Zelensky, there were 34 Russian airstrikes on Sunday alone.

Russia has repeatedly stated that its forces do not target civilians, and reporters reported seeing victims in uniform being pulled from the rubble. The Russian Ministry of Defense announced on Monday that it had targeted Ukrainian forces’ infrastructure in Chasiv Yar.

Following the capture of the entire eastern Luhansk region, Moscow has put its forces on “operational pause,” according to the Institute for the Study of War, as Russia shifts its focus to capturing the Donetsk region, which together with Luhansk forms the industrial Donbas region.

While the West transports modern weapons into Ukraine, Russia’s military has increased long-range missile strikes on positions far from the front lines.

Moscow has also used so-called long-range precision strikes on military bases and infrastructure far from the front lines. Some have resulted in mass casualties, such as at a train station in Kramatorsk, where nearly 60 people were killed and more than 100 were injured, and a shopping mall in Kremenchuk, where at least 20 people were killed.

The governor of Ukraine’s Kharkiv region, Oleh Synyehubov, said Russian missile attacks began there around 3:40 a.m. on Monday. According to him, one missile destroyed a school and another rocket struck a six-story residential building. Several people were hurt, he wrote on Telegram, but no fatalities were reported.

Though strikes have continued across the country, Moscow has focused its firepower on the Donetsk region. Russia and pro-Russian separatist forces already control a portion of the province, including Donetsk, the provincial capital. Capturing the remainder of the province would give Moscow complete control of the Donbas region, which the Kremlin prioritized after withdrawing its forces from central Ukraine in late March.

According to the Ukrainian Ministry of Defense, several parts of the Donetsk region have been hit with barrel bombs, the use of which in populated areas is prohibited by the United Nations. Furthermore, there were “signs of enemy units preparing to intensify combat operations in the Kramatorsk and Bakhmut areas,” according to the ministry.

Since the full-scale invasion began in February, 593 civilians have died and 1,550 have been injured in the Donetsk region, according to Pavlo Kyrylenko, head of the Donetsk regional military administration.

Meanwhile, Ukrainian forces are preparing a counteroffensive in the southern Kherson region, according to the Institute for the Study of War, and officials have advised civilians to flee the area. According to the British Ministry of Defense, neither side has made significant territorial gains in recent days.

Europe was bracing for a sharp reduction in the flow of natural gas from Russia on Monday, as the Nord Stream pipeline was set to shut down for 10 days of annual maintenance. European governments are concerned that the pipeline, which is the main route for Russian gas to Germany, will not reopen after Moscow reduced gas deliveries through the conduit by 40% in recent weeks.

Moscow has blamed the cuts on Western sanctions, which it claims are depriving the pipeline of critical equipment, including a turbine that has been repaired in Canada. Ukrainian officials chastised Canada for returning the turbine to Germany for use in Nord Stream. Berlin wants to return it to Russia, saying the move would show that Moscow has been using the turbine as an excuse for a political decision to cut gas deliveries to Europe.