HIROSHIMA, Japan -- Ukrainian President Volodymyr Zelenskyy is poised for a first post-invasion trip to the Asia-Pacific, meeting allies at a G7 summit in Hiroshima as the bloc hit Russia's "war machine" with further sanctions.

The previously unannounced visit was revealed by officials Friday -- a rare long-haul foray for the war-time president and an opportunity to huddle with leaders of seven wealthy democracies that bankroll his country's stoic defence.

The visit comes at a potentially pivotal time in the 15-month-old conflict, as Ukranian troops push back against Russian gains at Bakhmut and ready a long-awaited spring offensive.

Top Zelenskyy security aide Oleksii Danilov said the Ukrainian leader would go "wherever the country needs him, in any part of the world," including Hiroshima, a city synonymous with the horrors of war.

"Very important things will be decided there, and therefore the presence, the physical presence of our president is absolutely essential to defend our interests," Danilov said.

An informed source in Hiroshima told AFP that Zelenskyy was now expected to appear in person, though the timing of his arrival remained unclear.

The trip will also give Ukraine's president an opportunity to win over powerful unaligned nations, including Brazil and India, whose leaders have also been invited.

Zelenskyy recently embarked on a European tour, pleading for military support like modern US-made fighter jets, as well as tougher sanctions on Russia.

On Friday he arrived on an unannounced visit to Jeddah to address Arab League leaders gathered in the Saudi Arabian city.

"There are a host of things that Ukraine will continue to need, from artillery shells to sophisticated air defense systems," said Ian Lesser of the German Marshall Fund foreign policy think tank.

Securing the transfer of US F-16 fighter jets, of which there are "very large numbers in Europe that could be sent to Ukraine," will also likely be on the agenda, he added.

On the eve of his Japan visit, Group of 7 nations agreed new sanctions that they said would "starve Russia of G7 technology, industrial equipment and services that support its war machine."

The G7 statement also pledged to "restrict trade in and use of diamonds mined, processed or produced in Russia," including with the use of tracing technologies.

The trade is estimated to be worth about $4-5 billion a year for Russia.

"Russian diamonds are not forever," said EU Council President Charles Michel. "We will restrict trade."

EU member state Belgium is among the largest wholesale buyers of Russian diamonds, along with India and the United Arab Emirates.

The United States is a major end-market for the finished product.

The grouping also said they would step up efforts to prevent circumvention of their existing sanctions regime, "including targeting entities transporting material to the front."

Earlier Friday, the United States and other members announced their own new measures, with a senior US administration official saying another 70 entities from Russia and "other countries" would be placed on a US blacklist.

"And there will be upwards of 300 new sanctions against individuals, entities, vessels and aircraft," the official said.

London, meanwhile, took aim at Russian copper, aluminium and nickel -- as well as diamonds.

Moscow's invasion of Ukraine 15 months ago has prompted waves of sanctions that have helped plunge Russia into recession and drained the Kremlin's war chest.

The Russian economy contracted 2.1 percent in 2022, a trend that continued early this year.

But Moscow has adapted quickly, introducing strict capital controls, diverting trade to allies like China and reportedly borrowing evasion techniques from much-sanctioned countries like Cuba, Iran and North Korea.

The International Monetary Fund has projected a modest 0.7 percent economic rebound in 2023.

Earlier Friday, G7 leaders visited Hiroshima's peace park memorials and museum, where they saw evidence of the suffering and devastation caused by the 1945 atomic bombing of the city.

In a moment heavy with symbolism, they laid wreaths at the Hiroshima cenotaph, which commemorates the estimated 140,000 people killed in the attack and its aftermath. (AFP)