MOSCOW - A top Russian official told Ukraine on Tuesday that the longer it waited to enter peace talks, the tougher the terms would be for its people.

Moscow has said talks must be based on Ukraine ceding land amounting to a fifth of its territory - much of it seized by Russian forces - and renouncing any prospect of joining the Western-led NATO alliance, terms that Ukraine has dismissed out of hand.

Sergei Shoigu, secretary of Russia's Security Council and until recently President Vladimir Putin's defence minister, said that since Putin had proposed peace terms on June 14, Ukraine had lost 420 sq km (162 sq miles) of territory and much blood.

"The window of opportunity for Ukraine is narrowing," he was shown saying by state television, adding that Ukraine had not responded and would lose more territory the longer it delayed.

"The Kyiv regime's illusions that the Europeans will arrange another beautiful peace summit, ... at which all their internal problems will be resolved by themselves, are costing the people of Ukraine dearly," Shoigu said.

He gave a figure for Ukrainian troop losses but Reuters cannot verify such numbers, and neither side enumerates its own casualties.

Having sent in its troops in 2022, Russia now controls about 18% of Ukraine including Crimea, which it seized and unilaterally annexed in 2014.

It also holds swathes of four regions in southeastern Ukraine that Putin, claiming historical and cultural justification, says Kyiv must cede in their entirety.

Reuters has reported that Putin is ready to halt the war with a negotiated ceasefire that recognises the current battlefield lines, but is prepared to fight on if Kyiv and the West do not respond.

Ukrainian Foreign Minister Dmytro Kuleba said last month that Kyiv was prepared for talks provided Ukraine's sovereignty and territorial integrity, recognised by the vast majority of U.N. member states, were fully respected.

  - Reuters