Ukrainian President Volodymyr Zelenskyy on Monday urged world leaders gathered at the G7 summit to do their utmost to end Russia's invasion of his country by the end of the year, a source told AFP.
In his closed-door address via video link to the gathering of leaders in the German Alps, Mr Zelenskyy said battle conditions would make it tougher for his troops as they mount their fightback.
A war pushing past winter also risked raging further beyond, he said. He, therefore, urged the G7 leaders to do their maximum to end the war by year's end, including by intensifying sanctions against Russia, the source said.
Despite the multiple rounds of punitive measures that Western allies have unleashed on Moscow, Mr Zelenskyy pleaded with them to "not lower the pressure and to keep sanctioning Russia massively and heavily".
Claims about default 'absolutely wrong': Kremlin
Meanwhile, the Kremlin insisted on Monday there were "no grounds" to say Russia had defaulted on its foreign-currency sovereign debt as the West pummels Russia with sanctions over its Ukraine offensive.
"There are no grounds to call this situation a default," Kremlin spokesman Dmitry Peskov told reporters after a key payment deadline expired Sunday.
"These claims about default, they are absolutely wrong," he said, adding that Russia settled the debt in May.
Bloomberg News reported earlier on Monday that Russia defaulted on its foreign-currency sovereign debt for the first time in more than a century, after the grace period on some $100 million of interest payments due Sunday had expired.
The Russian authorities have accused the West of seeking to drive Moscow into an artificial default, and Finance Minister Anton Siluanov has dismissed the situation as a "farce".
Punishing Western sanctions on Russia have largely severed the country from the international financial system, making it difficult for Moscow to service its debt.
The country last defaulted on its foreign currency debt in 1918, when Bolshevik revolution leader Vladimir Lenin refused to recognise the obligations of the deposed tsar's regime.
It defaulted on ruble-denominated debt in 1998 amid a broader financial crisis.