US President Joe Biden and Ukraine’s Volodymyr Zelenskyy sign security deal

President Joe Biden and Ukrainian President Volodymyr Zelensky, left, shake hands after signing a security agreement on the sidelines of the G7 in Savelletri, Italy (Alex Brandon/AP)

US President Joe Biden and Ukrainian President Volodymyr Zelenskyy have signed a long-term agreement designed to bolster Ukraine’s defences against Russia’s invasion.

Mr Zelenskyy thanked Mr Biden for the pact but said “the question has to be for how long the unity will last”, given upcoming US elections and the prospect of Republican Donald Trump returning to the White House.

Mr Biden tried to reassure Mr Zelenskyy.

President Joe Biden and Ukrainian President Volodymyr Zelensky arrive to sign a bilateral security agreement on the sidelines of the G7 in Savelletri, Italy (Alex Brandon/AP)

“They’ll have what they need,” Mr Biden said, referring to Ukraine.

Both men spoke on the sidelines of the annual Group of Seven summit, held this week in southern Italy.