Ukraine's military said Monday its forces downed two of three cruise missiles that Russia fired from the Black Sea as well as seven of eight Iranian-made Shahed drones launched by Russia.

Such aerial attacks have been a common part of Russia's invasion of Ukraine, with Ukrainian officials hailing the work of air defenses in countering the assaults.

Ukrainian President Volodymyr Zelenskyy said in his nightly address Sunday after a phone call with U.S. President Joe Biden that he was "especially grateful" to the United States for the reliability of Patriot air defense batteries.

Biden reaffirmed unwavering U.S. support for Ukraine, including through continued security, economic and humanitarian aid, according to a White House statement.

Zelenskyy said he also discussed the fighting on the front lines and strengthening Ukraine's troops in his call with Biden and similar conversations Sunday with Canadian Prime Minister Justin Trudeau and Polish President Andrzej Duda.

Ukraine Deputy Defence Minister Hanna Maliar said Monday that Ukrainian forces had made some gains in the eastern part of the country during the past week, and that there was heavy fighting ongoing in the Lyman, Bakhmut, Avdiivka and Maryinka areas.

Maliar also said that while "the situation in the south has not undergone significant changes over the past week," overall Ukrainian forces had freed 130 square kilometers since launching a counteroffensive earlier this month.

US, Ukrainian reaction

The unprecedented challenge to Russian President Vladimir Putin by fighters from the Wagner paramilitary forces has exposed fresh "cracks" in the strength of Putin's leadership that may take weeks or months to play out, U.S. Secretary of State Antony Blinken said Sunday in a TV interview on the NBC program "Meet the Press."

Blinken characterized Wagner Group's mutiny and its subsequent crisis as a Russian "internal matter."

He added, "This is a challenge coming from within to Putin, and that's where his focus has been. Our focus is resolutely and relentlessly on Ukraine making sure that it has what it needs to defend itself and to take back territory that Russia has seized."

Blinken said that although it is too soon to tell what Russia's internal turmoil meant, Putin's distraction is to the advantage of Ukraine. He also said that at the end of the day, the reason Ukraine will prevail is that "this is about their land, this is about their future, this is about their freedom, not Russia's."

Ukrainian Defense Minister Oleksii Reznikov said he discussed the turmoil in Russia in a phone call with his U.S. counterpart Sunday, describing the Russian authorities as "weak" and saying things were "moving in the right direction."

In a brief readout of the call with U.S. Defense Secretary Lloyd Austin, Reznikov said they also discussed Ukraine's counteroffensive and steps to strengthen Ukraine's armed forces.

"We agree that the Russian authorities are weak and that withdrawing Russian troops from Ukraine is the best choice for the Kremlin," Reznikov wrote on Twitter. (VOA/NS)