MOSCOW: Ukraine hit a Moscow oil refinery for a second time in a week and disrupted commercial flights at Moscow airports in one of its biggest drone attacks since Russia's invasion more than four years ago, Russian officials said Thursday.

The Russian Defence Ministry said that its air defences overnight shot down 555 Ukrainian drones over multiple regions, with almost 200 intercepted as they were approaching the Russian capital.

Several drones hit the Moscow Oil Refinery on the southeastern outskirts of the city, Moscow Mayor Sergei Sobyanin said.

Zelenskyy said Wednesday his country had won key pledges of further support from world leaders attending the G7 summit in France.

"These last few days were very important for Ukraine because it is the reunification of the G7 around Ukraine," Macron told reporters as he and Trump left the Palace of Versailles near Paris.

"And now we will continue to advance to help Ukraine to resist and to build up its capacity to defend itself and capacity to counterattack," Macron said.

The attack comes as President Vladimir Putin is in Kazan, 700 kilometres (430 miles) east of Moscow, hosting leaders of the Association of Southeast Asian Nations as Russia seeks to bolster business and other ties.

The two-day meeting is set to consider ways to expand Russia's “strategic partnership” with ASEAN nations that include Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, East Timor and Vietnam, according to Kremlin foreign affairs adviser Yuri Ushakov.