LIVE - Updated at 05:51
Ukrainian president set to join summit; new raft of sanctions will target Russian exports, close loopholes and target individuals.
Explosions were reported this morning in widely separated regions, Reuters reports, including Kriviy Rih in central Ukraine and Rivne and Lutsk in the west.
Ukraine's military had said on Telegram that Russian aircraft were in the air and there was a threat of strikes from hypersonic Kinzhal missiles. An earlier military statement said some airborne targets had been downed, but gave no details.
The military had warned that central regions and Kyiv were at risk from drones.
Russia's Tass news agency, quoting Russian-installed officials in the Moscow-controlled area of Donetsk region, said Ukrainian forces had fired eight grad missiles into the Russian-held city of Donetsk after midnight.
There were no details of damage or casualties.
Reuters was unable to verify details of any of the reported military activity.
Air raid alerts sounded throughout Ukraine early on Friday, with some areas later reporting explosions and officials saying anti-aircraft units were in action in several regions.
The alerts extended to all regions of the country for about an hour from 2am local time, Reuters reports.
But there were no reports of strikes on infrastructure or civilian targets and no indications of casualties as the alerts were withdrawn in Kyiv and in central and southern regions.
The head of Kyiv's military administration said Russian forces had sent successive waves of drones towards the capital, the 10th attack this month and the second in less than 24 hours.
"This Kremlin tactic is an attempt to overwhelm our anti-aircraft forces and put psychological pressure on civilians. It won't happen!" Serhiy Popko wrote on Telegram.
"All air targets sent toward Kyiv were destroyed by our anti-aircraft defences."
Several regions reported anti-aircraft units in operation.
Japanese media say that the G7 leaders' communique is expected to include a call for countries to stop providing weapons to Russia to prosecute its war in Ukraine.
Citing unnamed Japanese government officials, the Asahi Shimbun said discussions would focus on how G7 countries could close loopholes to strengthen sanctions against the Kremlin.
The communique is expected to resemble a statement issued by G7 foreign ministers last month that urged countries to stop providing Russia with products that could be converted for military use "or face severe costs", the newspaper said.
US sanctions would "cut off roughly 70 entities from Russia, and other countries, from receiving US exports by adding them to the commerce blacklist. And there will be upwards of 300 new sanctions against individuals, entities, vessels and aircraft" an American officials said.
The US and its allies, including the EU and Britain, have continued to ratchet up sanctions and export-control pressure on Russia since the invasion of Ukraine began in February 2022.
Related: G7 leaders prepare new Russia sanctions as Zelenskiy expected to attend Japan summit
At the G7 today and over the weekend, leaders of the group of major economies will unveil further sanctions and export controls targeting Russia over its war against Ukraine, as it was reported that the Ukrainian president, Volodymyr Zelenskiy, would attend the Hiroshima summit in person.
The Russian invasion of Ukraine, now in its second year, will be high on the agenda as G7 leaders gathered in Hiroshima on Friday. The US has spearheaded tough sanctions on Russian companies, banks and individuals; the forthcoming announcements are designed to reaffirm world powers' resolve to support Ukraine and squeeze Moscow.
A US official, speaking to reporters ahead of the gathering, said the G7's latest efforts were aimed at disrupting Russia's ability to get materials it needs for the battlefield, close loopholes used to evade sanctions, further reduce international reliance on Russian energy, and narrow Moscow's access to the international financial system.
Related: G7 leaders prepare new Russia sanctions as Zelenskiy expected to attend Japan summit
Ukrainian President Volodymyr Zelenskiy will travel to Japan to join G7 leaders at the summit in Hiroshima, a European Union source has told Reuters.
Bloomberg is also reporting Zelenskiy's surprise in-person visit, citing people familiar with the matter.
Zelenskiy had been expected to make a virtual appearance.
Welcome back to our live coverage of the war in Ukraine with me, Helen Sullivan.
Our top stories this morning: Ukrainian President Volodymyr Zelenskiy will travel to Japan to join the G7 summit in Hiroshima in person, Reuters and Bloomberg report, citing unnamed people familiar with the matter. Zelenskiy had been expected to appear via video link.
G7 leaders are set to announce new sanctions against Russia during the gathering in Hiroshima. The measures are expected to disrupt Russia's ability to get materials it needs for the battlefield, close loopholes used to evade sanctions, further reduce international reliance on Russian energy, and narrow Moscow's access to the international financial system.
More on these stories shortly.
In the meantime, here are the other key recent developments:
The United States and the rest of the Group of Seven major economies will unveil new sanctions and export controls targeting Russia, a US official has said ahead of a G7 summit in Japan. The G7's latest efforts were aimed at disrupting Russia's ability to get materials it needed for the battlefield, closing loopholes used to evade sanctions, further reducing international reliance on Russian energy and narrowing Moscow's access to the international financial system, the official told reporters on Thursday.
The UK unveiled a swathe of new sanctions ahead of the meeting. The British prime minister, Rishi Sunak, announced a UK ban on imports of Russian diamonds and Russian-origin copper, nickel and aluminium. Sunak also has a self-declared mission to push India into showing greater support for Ukraine.
The Pentagon overestimated the value of the ammunition, missiles and other equipment it sent to Ukraine by about $3bn, a Senate aide and a defence official told Reuters on Thursday, an error that may lead the way for more weapons being sent to Kyiv for its defence against Russian forces.
Jack Teixeira, the US air national guard member charged with being behind the so-called Pentagon leaks, was warned repeatedly over his mishandling of classified material, court documents show. The leaked documents appear to detail US and Nato aid to Ukraine and show real-time details from February and March of Ukraine's and Russia's battlefield positions and the amounts of battlefield gear flowing into Ukraine from its allies.
Ukraine has used the long-range Storm Shadow missiles provided by Britain, the British defence minister, Ben Wallace, said. He also said on Thursday there was no doubt Russia had "the intent and the ability" to target the west's underwater energy and communication lines.
Ukraine said it had repelled a day of Russian attacks in and around the ruined eastern city of Bakhmut on Thursday and made gains of a kilometre in some places while buying time for "certain planned actions".
Russia launched missiles overnight at Kyiv again, with falling debris causing a fire at a business building, authorities reported. It was the ninth time this month that Russian air raids have targeted the capital, a clear escalation after weeks of lull and ahead of a much-anticipated Ukrainian counteroffensive.
A person was killed in Russian missile strikes on Odesa, military administration spokesperson Serhiy Bratchuk has said on Telegram. Two people were injured. A person was also killed in Kostyantynivka, in the Donetsk region.
The Russian defence ministry has said it struck Ukrainian military targets using high-precision missiles. The claim on Thursday came a day after a major wave of missile strikes on Ukrainian cities, the Russian state-owned news agency Tass reported.
The Black Sea grain corridor designed to ensure the safe supply of Ukrainian food to world markets has not yet resumed operation despite statements by Turkey and Russia on extending the agreement, a senior Ukrainian official said on Thursday. The deal was extended for two months on Wednesday.
Rail traffic was suspended between Simferopol, capital of the Crimean peninsula, and the city of Sevastopol after a freight train carrying grain derailed, the region's Russian-installed leader said on Thursday. The derailment was caused by "interference by outsiders", Crimean railways said.
The Kremlin has confirmed that a delegation from African countries hoping to present their initiative to end the conflict in Ukraine would visit Moscow. Kremlin spokesperson Dmitry Peskov said Moscow would be ready to listen to "any proposals" that helped resolve the conflict.