Ukraine is bracing for the most difficult winter year of the Russian invasion, launched by the Kremlin in February 2022.

More than two and a half years into the war, Kyiv is losing new territory almost daily in its eastern Donbas region and under mounting pressure to forge an exit strategy -- which it says must start with ramped-up Western support.

Zelensky's comments came days after visiting several European capitals to press his case for more military and financial help in the war against invading Russian forces.

The chair of the House Oversight Committee said the goal is determining whether the government "attempted to use a foreign leader to benefit the Vice President's presidential campaign"

Zelensky will present his proposals -- which he calls a "victory plan" -- to President Joe Biden, as well as presidential hopefuls Kamala Harris and Donald Trump.

Russian attack drones flying towards Ukraine also breached the airspace of NATO members Romania and Latvia, the countries said Sunday, triggering calls for a robust response from the military alliance.

He will also meet German Chancellor Olaf Scholz and then head to Italy, following the meeting at Ramstein Air Base, which comes days after 55 people were killed and 300 wounded in a Russian missile strike on the city of Poltava.

Moscow has stepped up its aerial attacks after Ukraine's offensive in Russia's Kursk region, which caught Russian troops by surprise.

Donetsk has been partially controlled by Russian proxy forces since they wrested control over swathes of the industrial territory in 2014.

The premier has trodden a delicate balance between maintaining India's historically warm ties with Russia while courting closer security partnerships with Western nations as a bulwark against regional rival China.

AFP journalists saw dozens of Ukrainian military vehicles daubed with white triangles, the insignia apparently used to identify forces involved in Kursk operation, kicking up dust on roads in the Sumy border territory.

Moscow's defence ministry said it had rushed its troops and aviation units to the border in southwestern Kursk region after a morning raid by Ukrainian units -- the latest such attack throughout the conflict.

For more than two years, Ukraine has pleaded with its Western partners for the aircraft -- long considered the crown jewel in the sprawling list of military hardware Kyiv has sought.

The announcement came as Ukrainian President Volodymyr Zelensky visited special forces in the border region of Kharkiv, where Moscow's forces launched a surprise ground offensive in May but failed to make any major breakthrough.

With its castle, medieval tower and river-side beach, the western Ukrainian tourist town of Starokostiantyniv doesn't seem an obvious target for Russian missile and drone strikes.

Russia said Sunday its forces had captured two frontline villages in Ukraine, Andriivka in the eastern Lugansk region and Pishchane in the northeast Kharkiv region.

Zelensky said on Monday that Russia "should be" represented at a second summit on the Ukraine conflict, following high-level talks last month in Switzerland that Moscow did not attend and heavily criticised.

Last year, NATO's failure to issue Ukraine a clear timeframe for membership did not go down well.

Presidents Joe Biden and Volodymyr Zelensky signed a landmark 10-year security deal between Washington and Kyiv on Thursday in what the Ukrainian leader called a historic day in the fight against Russia's invasion.

Zelensky, who is also due to address the German parliament, will join the heads of the G7 developed nations later this week in Italy.

Switzerland will stage a conference on Ukraine this coming weekend, with world leaders set to discuss how to reach an eventual peace process -- although Russia is not taking part.

Macron said he would offer Ukrainian President Volodymyr Zelensky when the two meet for talks at the Elysee Palace in Paris on Friday that the pilots be trained from this summer.

Ukrainian President Volodymyr Zelensky accused China on Sunday of working hard to stop countries from going to a peace summit, which Beijing has publicly criticised because Russia is not invited.

Russia has added Ukrainian President Volodymyr Zelensky to its list of wanted criminals, a move Kyiv dismissed as a sign of Moscow's "desperation".

Rescuers were removing mountains of rubble on Thursday from the site of a lethal Russian missile strike on Ukraine's historic city of Chernigiv, where at least 18 people were killed in an attack that has prompted fresh pleas for allies to boost Kyiv's overstretched air defense systems.

Ukrainian President Volodymyr Zelensky called on the West to deliver air defence systems after the attacks, which wounded 17 in Kyiv and the surrounding region.

Biden said the stopgap shipment of missiles, shells and ammunition for Kyiv was "not nearly enough" and would run out in a couple of weeks.

For the Ukrainian troops holding Russian forces from cities like Kostyantynivka, the task is becoming harder as their resources and stamina ebb.

A heightened Russian offensive in eastern and southern Ukraine saw them capture the key town of Avdiivka last week in a major boost ahead of the second anniversary of the February 2022 invasion.

As President Volodymyr Zelensky headed for Berlin and Paris in a new bid to secure desperately needed military aid, Ukrainian generals said there was bitter fighting inside Avdiivka and that their forces were taking up "new positions".