The Russian Ministry of Defense (MOD) said Moscow's forces have taken control of the settlement of Novokhatske in the eastern Ukrainian region of Donetsk and also defeated various Ukrainian brigades in several areas of Sumy, Kharkiv and Mykolaiv.
The latest advances come after President Donald Trump set Moscow a 50-day deadline to agree to a peace deal, or he would introduce deeper sanctions against the Russian economy, including a punitive secondary tariff on its trading partners.
Trump also said he is sending Ukraine more Patriot air defense missiles, as well as other "sophisticated" weapons that would be paid for by NATO allies in Europe, in a hardening of his stance against Moscow.
Russia has continued to pound Ukrainian cities with drone and missile strikes, and pushed its forces on in the country's east, despite Trump's efforts to broker peace.
The intensification of Russian action in Ukraine has frustrated Trump, who feels he has been misled by President Vladimir Putin in their recent conversations.
Putin has expressed a desire for peace, but also told Trump that he intends to achieve his war goals in Ukraine.
Latest Russia-Ukraine War News
In its latest operation update, the General Staff of the Armed Forces of Ukraine noted "large-scale armed aggression" by Russia and a wave of new attacks.
But it said Ukrainian soldiers "are inflicting tangible losses" on the Russians, both in manpower and equipment, and "actively suppress the enemy's offensive potential."
The Ukrainian Air Force said separately that Russia had launched 400 Shahed drones and an Iskander-M ballistic missile overnight into Wednesday, July 16.
Of these, 198 were shot down, the air force said, and 145 decoy drones were neutralized. But the missile and 57 drones hit their targets.
The strikes targeted northeastern Kharkiv, which is Ukraine's second-largest city, President Volodymyr Zelensky's hometown of Kryvyi Rih in central Ukraine, Vinnytsia in the west and Odesa in the south.
"Russia does not change its strategy," Zelensky said. "To effectively counter this terror, we need a systemic strengthening of defense: more air defense, more interceptors, and more resolve so that Russia feels our response."
Trump 50-Day Deadline
Some U.S. lawmakers and European government officials expressed misgivings that Trump's 50-day deadline handed Putin the opportunity to capture more Ukrainian territory before any settlement to halt the fighting.
Other U.S. ultimatums to Putin in recent months have failed to persuade the Russian leader to stop his invasion.
Tens of thousands of soldiers have been killed in the war, many of them along the more than 1,000-kilometer (620-mile) front line, and Russian barrages of cities have killed more than 12,000 Ukrainian civilians, the United Nations says.
The Institute for the Study of War, a Washington think tank, said Tuesday: "Putin holds a theory of victory that posits that Russia can achieve its war aims by continuing to make creeping gains on the battlefield indefinitely and outlasting Western support for Ukraine and Ukraine's ability to defend itself."
This article includes reporting by The Associated Press.
