ELMAU CASTLE, June 28 (AFP) - President Volodymyr Zelenskyy on Monday (Jun 27) urged world powers to do their utmost to help end Russia's invasion by the end of the year, as Group of Seven (G7) leaders planned new sanctions and vowed to support Ukraine "as long as it takes".

US President Joe Biden and his counterparts from the G7 rich nations, meeting for three days in the Bavarian Alps, promised to tighten the economic screws on Moscow over its Feb 24 invasion.

They also put on a show of unity over Ukraine, even as the fallout from the war intensifies with soaring energy and food prices driving up global inflation.

"We will continue to provide financial, humanitarian, military and diplomatic support and stand with Ukraine for as long as it takes," the G7 said in a statement on the summit's second day.

Addressing the gathering via video link, Zelenskyy urged leaders to help end the war before winter sets in and conditions for his troops become tougher.

He urged allies to keep up the pressure and "intensify sanctions" on Moscow, including by imposing an oil price cap to limit Russia's energy revenues.

German Chancellor and summit host Olaf Scholz signalled the G7's readiness to do more, saying: "We will continue to increase pressure on (Vladimir) Putin. This war has to come to an end."

Among the new steps being discussed by G7 leaders is the price cap on Russian oil imports sought by Zelenskyy and sanctions targeting Russia's defence industry.

Washington meanwhile is planning to send Ukraine sophisticated anti-aircraft missiles, a source familiar with the process told AFP.

Zelenskyy has long asked allies for more powerful defences against Russian attacks.

An announcement is "likely this week" on the purchase of an "advanced medium to long-range surface-to-air missile defence system", the source said.

The summit of the G7 - which comprises the US, Germany, Britain, France, Italy, Japan and Canada - ends on Tuesday.

It will immediately be followed by a meeting of NATO countries in Spain, where Ukraine is again expected to dominate the agenda.