US President Joe Biden meets with Ukrainian President Volodymyr Zelenskiy, during the G7 Summit at the Grand Prince Hotel in Hiroshima, Japan, May 21, 2023
Hiroshima, Japan CNN  — 

Group of Seven talks culminated Sunday with a series of dramatic, in-person appeals from Ukrainian President Volodymyr Zelensky as he pressed leaders gathered in Japan to remain united against Russian aggression.

Zelensky’s decision to travel halfway across the world to deliver his entreaties to the world’s major industrial democracies in person underscored both the unity and the uncertainty leaders find themselves in fourteen months since Russia’s unprovoked invasion of Ukraine began.

It also came as Russia’s Wagner mercenary group claimed to have finally taken the Ukrainian city of Bakhmut, the scene of bitter fighting for months.

In a striking morning photo-op in a city once obliterated by a nuclear bomb, leaders in suit jackets lined up alongside the Ukrainian president, dressed in his usual military green, to show their sustained support for his country moving ahead.

Something of a sudden star appearance – his presence was only confirmed at the last minute on Saturday – Zelensky used the final day of the gathering to continue his appeals for more powerful weapons and tougher sanctions against Moscow.

“As long as invaders remain on our land, no one will sit down at the negotiating table with Russia,” Zelensky wrote on Twitter, adding that “the world has enough power to force Russia to restore peace step by step.”

“Our world is vast, but we are all in it together,” Zelensky added. “From Japan to the Arab countries, from Europe to Latin America, we find support for our formula. And we continue this work,” he added.

Throughout the weekend Ukraine’s wartime leader engaged in a frenetic series of meetings, including with US President Joe Biden, their first since the latter visited Kyiv in February.

Biden announced a new $375 million security assistance package to Ukraine.

“The United States continues to do all we can to strengthen Ukraine’s ability to defend itself,” Biden said, citing his recent decision to allow F16 fighter jets to go to Ukraine and to train Ukrainian pilots on the aircraft in the United States.

“Together with the entire G7, we have Ukraine’s back and I promise we’re not going anywhere,” he added.

Bakhmut’s fate is a stark illustration of what is at stake for Ukraine.

In his meeting with Biden, Zelensky denied the city had been taken but said little remained.

“They destroyed everything. There are no buildings. It’s a pity, it’s a tragedy, but for today Bakhmut is only in our hearts,” he said.

Ukraine’s military has also disputed Wagner’s claim that Bakhmut has been taken, saying the battle is still ongoing.

Kyiv has been bolstered by ever-more-advanced weaponry weaponry from Western nations.

British Prime Minister Rishi Sunak said the United Kindgom will begin training Ukrainian pilots on US-made F-16 fighter jets “this summer” to “support Ukraine’s air force with what it needs for the future”.

“Ukraine must not only win the war but win a just and lasting peace,” Sunak told reporters in Hiroshima on Sunday.

Waning support and political deadlock?

But there are fears that fatigue and political pressure could eventually cause Western support to wane.

Dysfunction in Washington, starkly illustrated this past week by deadlocked negotiations over raising the federal borrowing limit, also contributed to questions among G7 leaders over how much longer political support for Ukraine can be sustained.