Ukrainian President Volodymyr Zelenskyy told Luxembourg's parliament in a video address on Thursday that Russia "occupies" about 20 percent of Ukraine's territory at present, Reuters reported.

"We have to defend ourselves against almost the entire Russian army. All combat-ready Russian military formations are involved in this aggression," he said, adding that the front lines of battle stretched across more than 1,000 kilometers.

Later on the same day, addressing the GLOBSEC 2022 Bratislava Forum in the Slovak capital by video link, Zelenskyy said while Ukraine is grateful for all assistance received, weapons supplies to Ukraine need to be stepped up.

(With input from Reuters)