US President Joe Biden and Ukrainian leader Volodymyr Zelensky have signed a 10-year security agreement that they hailed as a milestone in relations between their countries.

But that alone was not enough to stop Mr Zelensky from wondering how much longer he could count on America’s support.

Mr Zelensky also said his country “urgently” needed additional air defence systems to protect Ukrainians and the nation’s infrastructure from Russia’s continued bombardment.

The leaders signed the agreement on the sidelines of the annual Group of Seven summit, held this year in Italy, and Mr Biden said the goal “is to strengthen Ukraine’s defence and deterrence capabilities”.

Mr Zelensky said at a joint news conference that the signing made for a “truly historic day”, but he also wondered about the durability of support from the United States and other allies.

Ukraine’s president said the right question to ask is “for how long the unity in the world will remain? The unity in the US, together with European leaders” and how it will be influenced by the outcome of elections this year in many of those countries.

Topping that list is voting in the US in November in a campaign that could see the return of Republican Donald Trump to the presidency.

Mr Trump has been sceptical of providing additional military aid to Ukraine, at one point criticising the “endless flow of American treasure”.

He more recently has expressed openness to lending money instead and has said Ukraine’s independence is important to the United States.

Mr Zelensky went on to deliver a stark warning about Russian aggression, saying that “if Ukraine does not withstand, the democracy of many countries, I am sure, won’t withstand either”.

The US and European countries also agreed to keep sanctioned Russian assets locked up until Moscow pays reparations for its invasion of Ukraine, clearing the way for a 50 billion dollar (£39 billion) loan package for Ukraine.

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

Combined with new sanctions against Russia announced earlier in the week, Mr Biden said the series of actions to support Ukraine show Russian President Vladimir Putin that “he cannot wait us out. He cannot divide us”.

The highly anticipated agreement will leverage interest and income from more than 260 billion dollars (£203 billion) in frozen Russian assets, largely held in Europe, to secure a 50 billion dollar loan from the US and additional loans from other partners.

Ukraine will receive the first payments sometime this year, but it will need time to use all the money, a US official said on Thursday.

The official spoke on the condition of anonymity to preview the agreement, which will be included in the G7 leaders’ communique on Friday.

Ukraine will be able to spend the money in several areas, including for military, economic, humanitarian and reconstruction needs, the official said.

The leaders’ statement on Friday will also leave the door open to confiscating the Russian assets entirely, for which the allies have yet to secure the political will, largely citing legal and financial stability concerns.

Mr Biden and Mr Zelensky met on Thursday for the second time in two weeks to discuss the security agreement as the international group of wealthy democracies has been looking for new ways to bolster Ukraine’s defences against Russia.

The agreement on how to use the frozen Russian assets to benefit Ukraine comes several months after the White House broke through a logjam in Congress that stalled approval of some 60 billion dollars (£47 billion) in US aid for Ukraine.

Ukraine’s President Volodymyr Zelensky talks to journalists during a news conference after signing a bilateral security agreement with US President Joe Biden during the sidelines of the G7 summit at Savelletri, Italy
Ukraine’s President Volodymyr Zelensky talks to journalists during a news conference after signing a bilateral security agreement with US President Joe Biden during the sidelines of the G7 summit at Savelletri, Italy (Andrew Medichini/AP)

The delay gave Russia time to make up ground on the battlefield.

Mr Biden publicly apologised to Mr Zelensky for the hold-up when they met last week in France.

The agreement does not commit US troops directly to Ukraine’s defence against Russia.

That is a red line drawn by Mr Biden, who does not want the US pulled into a direct conflict with nuclear-armed Moscow.

The security pact, which would remain in effect for 10 years, does not offer Ukraine any new money but includes a commitment by the US to work with Congress on a source of sustainable funding for the future.

Text of the agreement released by the White House also describes how the US will co-ordinate with Ukraine and other US allies and partners to make sure Ukraine has the military, intelligence and other means necessary to defend itself and deter Russian aggression.

The US and Ukraine would also consult “at the highest levels” in the event of a future armed attack by Russia against Ukraine.

Either side may terminate the agreement in writing with six months’ notice, which means a future US president, including Mr Trump if elected in November, could cancel the arrangement.

President Joe Biden answers no to a question about pardoning his son as he shakes hands with Ukrainian President Volodymyr Zelensky after signing a bilateral security agreement on the sidelines of the G7 in Savelletri, Italy
President Joe Biden answers no to a question about pardoning his son as he shakes hands with Ukrainian President Volodymyr Zelensky after signing a bilateral security agreement on the sidelines of the G7 in Savelletri, Italy (Alex Brandon/AP)

Scores of countries and organisations are set to meet over the weekend in Switzerland to discuss peace for Ukraine.

Mr Biden is not scheduled to attend the summit, and that has disappointed Mr Zelensky.

Vice president Kamala Harris will represent the US instead while the Democratic president attends a campaign fundraiser in Los Angeles.

Mr Zelensky recently said the Swiss summit needs Mr Biden’s participation because other leaders value the US viewpoint.

He said Mr Biden’s absence “will be only an applaud to Putin, a personal applaud to Putin”.