Russian Foreign Minister Sergey Lavrov has issued an ultimatum for Ukraine saying Kyiv must meet Moscow's demands or its army will.
A day after President Vladimir Putin said he was open to negotiations over Ukraine, Lavrov lashed out at Kyiv and claimed that the West sought to destroy his country.
Kyiv and its Western allies have dismissed Putin's offer to talk, with his forces battering Ukrainian towns with missiles and rockets and Moscow continuing to demand that Kyiv recognize its conquest of a fifth of the country.
The Ukrainian capital says it will fight until Russia withdraws.
"Our proposals for the demilitarization and denazification of the territories controlled by the regime, the elimination of threats to Russia's security emanating from there, including our new lands, are well known to the enemy," state news agency TASS quoted Foreign Minister Sergei Lavrov as saying late Monday.
"The point is simple: Fulfil them for your own good. Otherwise, the issue will be decided by the Russian army."
Putin launched his invasion of Ukraine on Feb. 24, calling it a "special operation" to "denazify" and demilitarize Ukraine, which he said was a threat to Russia.
Kyiv and the West say Putin's invasion was merely an imperialist land grab. The United States and its allies have imposed sweeping sanctions on Russia for its invasion and sent billions of dollars in assistance to the Ukrainian government.
Just last week, when Ukrainian President Volodymyr Zelenskyy was visiting Washington, the United States announced another $1.85 billion in military assistance for Ukraine, including a transfer of the Patriot Air Defense System, angering Moscow.
"It is no secret to anyone that the strategic goal of the United States and its NATO allies is to defeat Russia on the battlefield as a mechanism for significantly weakening or even destroying our country," Lavrov further told TASS.
He reiterated that Russia and the United States cannot maintain normal connection, blaming the administration of U.S. President Joe Biden.
While Moscow had planned a swift operation to take over its neighbor, the war is now in its 11th month, marked by many embarrassing Russian battlefield setbacks.
In the latest attack to expose gaps in Russia's air defenses, a drone believed to be Ukrainian penetrated hundreds of kilometeres through Russian airspace on Monday, causing a deadly explosion at the main base for its strategic bombers.
Russian forces have been engaged for months in fierce fighting in the east and south of Ukraine, to defend the lands Moscow proclaimed it annexed in September and which make up the broader Ukrainian industrial Donbass region.
Over the past 24 hours, Ukrainian forces have repelled Russian attacks in the areas of two settlements in the Luhansk region and six in the Donetsk region, the General Staff of Ukraine's Armed Forces said Tuesday.
In his nightly video message on Monday, Zelenskyy called the situation along the frontline in Donbass "difficult and painful."
Oleh Zhdanov, a military analyst based in Kyiv, said heavy fighting was going on around elevated areas near Kreminna in the Luhansk region.
He also said that fighting has picked up along the Bakhmut and Avdiivka, a line of contact further south in the Donetsk region, after a brief easing in previous days.
"The arc of fire in Donetsk region continues to burn," Zhdanov said in a social media video post.
Zelenskyy said as a result of attacks on Ukraine's energy infrastructure nearly nine million people were without power. That figure amounts to about a quarter of Ukraine's population.
Sergey Kovalenko, head of YASNO, which supplies electricity to Kyiv, said late Monday that while the power situation has been improving in the city, blackouts will continue.
"While repairs are underway, emergency shutdowns will continue," Kovalenko said on his Facebook page.
Moscow on Monday said it had shot down a drone believed to be Ukrainian, causing it to crash at the Engels air base, where three service members were killed. Ukraine did not comment, under its usual policy on incidents inside Russia.
A suspected drone struck the same base on Dec. 5.
The base, the main airfield for the bombers that Kyiv says Moscow has used to attack Ukrainian civilian infrastructure, is hundreds of miles from the Ukrainian frontier. The same planes are also designed to launch nuclear-capable missiles as part of Russia's long-term strategic deterrent.
The Russian Defense Ministry said in a statement no planes were damaged, but Russian and Ukrainian social media accounts said several had been destroyed. Reuters was not able to independently verify the reports.
Putin hosted leaders of other former Soviet states in St. Petersburg on Monday for a summit of the Commonwealth of Independent States group, which Ukraine has long since quit.
The invasion of Ukraine has been a test of Russia's longstanding authority among other ex-Soviet states.
In televised remarks, Putin made no direct reference to the war, while saying threats to the security and stability of the Eurasian region were increasing.
"Unfortunately challenges and threats in this area, especially from the outside, are only growing each year," he said. "We also have to acknowledge unfortunately that disagreements also arise between member states of the commonwealth."
