Aboard Air Force One, 12 June

President Joe Biden and President Volodymyr Zelenskyy will sign a bilateral security agreement between the US and Ukraine on Thursday when they meet on the sidelines of the Group of Seven summit in Italy, aiming to send a signal to Russia of American resolve in supporting Kyiv, the White House said as Biden was headed to Europe.

National security adviser Jake Sullivan said the agreement would not commit US troops directly to Ukraine's defence against Russia's invasion — a red line drawn by Biden, who's fearful of being pulled into direct conflict between the nuclear-armed powers.

Announcement of the agreement comes as Biden heads to the summit of the world's leading democracies with an urgency to get big things done, including turning frozen Russian assets into billions of dollars to help Ukraine fight Russian President Vladimir Putin's war machine.

“We want to demonstrate that the US supports the people of Ukraine, that we stand with them and that we'll continue to help address their security needs,” Sullivan said, adding "this agreement will show our resolve”.

This year's meeting comes three years after Biden declared at his first such gathering that America was back as a global leader following the disruptions to Western alliances that occurred when Donald Trump was president. Now, there's a chance this gathering could be the final G7 for Biden and other G7 leaders, depending on the results of elections this year.

Biden and his counterparts from Canada, Britain, France, Germany, Italy and Japan will use the summit to discuss challenges related artificial intelligence, migration, the Russian military's resurgence and China's economic might, among other topics. Pope Francis, Zelenskyy and Turkish President Recep Tayyip Erdogan are joining the gathering at the Borgo Egnazia resort in the Puglia region of southern Italy.

The summit, opening Thursday, will play out after far-right parties across the continent racked up gains of surprising scale in just-concluded European Union elections. Those victories, coupled with upcoming elections in the United Kingdom, France and the United States, have rattled the global political establishment and added weightiness to this year's summit.

“You hear this a lot when you talk to US and European officials: If we can't get this done now, whether it's on China, whether it's on the assets, we may not have another chance,” said Josh Lipsky, senior director of the Atlantic Council's GeoEconomics Centre, an international affairs think tank. “We don't know what the world will look like three months, six months, nine months from now."

The G7 is an informal bloc of industrialised democracies that meets annually to discuss shared issues and concerns. Biden will arrive in Italy on Wednesday night, his second trip outside the US in as many weeks. The Democratic president was in France last week for a state visit in Paris and ceremonies in Normandy marking the 80th anniversary of the D-Day landings in World War II.

While last week's visit had a celebratory feel, this one will be dominated by pressing global issues, including how to keep financial support flowing to Ukraine as it fights Russia's invasion. Biden's trip comes a day after his son Hunter was convicted on federal gun charges, a blow sure to weigh heavily on the president's mind.

Despite pressing global challenges, White House national security spokesman John Kirby said there's still a sense of relief among world leaders in 2024 that "America was back", referencing Biden's 2021 speech at the G7 in England.