The group has urged Moscow to allow grain shipments to leave Ukraine and let Ukrainians taken to Russia against their will to return home.

"We urge Russia to behave responsibly and exercise restraint," G7 statement says. (AP)

The Group of Seven leaders have pledged to continue supporting Ukraine "for as long as it takes" in the face of the Russian onslaught.

"We will continue to provide financial, humanitarian, military and diplomatic support and stand with Ukraine for as long as it takes," said the G7 in a statement from its summit in southern Germany on Monday.

After speaking with Ukrainian President Volodymyr Zelenskyy for nearly two hours by video-link from Kiev, G7 leaders issued a forceful message of solidarity with the embattled nation.

Addressing Russia, the G7 said Moscow must allow grain shipments to leave Ukraine to avoid exacerbating a global food crisis.

"We urgently call on Russia to cease, without condition, its attacks on agricultural and transport infrastructure and enable free passage of agricultural shipping from Ukrainian ports in the Black Sea," it said.

READ MORE: G7 nations to ban Russian gold imports in response to Ukraine conflict: US

'Not the time'

The leaders also called for Moscow to allow Ukrainians taken to Russia against their will to return home at once.

"We demand that Russia immediately allow the safe return of Ukrainian nationals taken often with force to Russia without their consent," they said.

The club of rich nations expressed "serious concern" over Russia's stated plans to deliver missiles capable of carrying nuclear warheads to Belarus in the coming months.

"We urge Russia to behave responsibly and exercise restraint," the leaders said.

A G7 source said Zelenskyy had urged world leaders to do their utmost to end Russia's invasion of his country by the end of the year, as battle conditions would make it tougher for his troops as they mount a viable defence.

Zelenskyy stressed the need to keep heaping "heavy" punitive action on Russia, and "not lower the pressure" despite the multiple rounds of sanctions Western allies have unleashed on Moscow.

He said he was not ready to open negotiations with Russia, as Kiev is still seeking to consolidate its positions, the French presidency quoted him as saying.

"President Zelenskyy gave a very clear response that now is not the time for negotiations. Ukraine will negotiate when it is in a position to do so, that is, when it has basically re-established a position of strength," Emmanuel Macron's office said.

The Ukrainian leader later said on his Telegram account he had asked leaders to cap the price of Russian oil as a means of depleting the Russian war chest funded in large part by energy revenues.

READ MORE: G7 members seek to cap Russian oil price — German official

Source: TRTWorld and agencies