NATO Secretary General Mark Rutte on Tuesday said Ukraine could be facing its most challenging winter since Russia's war began in 2022. 

Rutte called on NATO allies to increase their arms supplies to support Kyiv ahead of what he described as a potentially brutal winter campaign.

"NATO must and will do more to help Ukraine," Rutte told journalists. "Russia continues to carry out massive strikes against Ukraine's critical energy infrastructure. Ukraine could be facing its toughest winter since the full-scale invasion began."

"The more military support we give, the faster this war will end," he added.

Rutte, who took over as NATO chief this month, emphasized the need for continued military and humanitarian support to Ukraine.

His comments follow a visit to Kyiv last week, where he assessed the situation on the ground and discussed further NATO aid with Ukrainian officials.

Rutte acknowledged that the situation on the battlefield remains "difficult" for Ukraine, particularly as Russian forces make incremental gains in the eastern regions. However, he stressed that these advances come at a significant cost to Moscow.

"We have to also take into account that the Russian losses are huge. They now stand at about, as far as we know, 1,000 killed and wounded each day," Rutte said, adding that total Russian casualties since the war began have reached around 500,000 killed or wounded.