The leaders of the Group of Seven nations have agreed to give Ukraine a $50 billion loan to address the fallout from President Vladimir Putin's continued war on Ukraine, a senior administration official said Thursday. 

The loan would be funded by interest earned on profits from Russia's frozen assets, largely held in Europe. The loan will fund military aid, humanitarian support and reconstruction costs. The move comes as Mr. Biden and Ukrainian President Volodymyr Zelenskyy signed a separate bilateral security agreement. The U.S.-Ukraine security agreement commits U.S. support to Ukraine for the next decade, including military training, intelligence sharing and weapons assistance. 

The U.S. president and the leaders of Italy, Canada, Germany, France, Canada and the United Kingdom are in Italy for a series of G7 meetings this week. Mr. Biden and Zelenskyy held a joint press conference in Italy on Thursday. 

"We've taken three major steps at the G7 that collectively show Putin he cannot wait us out," Mr. Biden said. "He cannot divide us. And we'll be with Ukraine until they prevail in this war. First is the bilateral security agreement just signed. Second, historic agreement to provide $50 billion in value from Russian sovereign assets to Ukraine. And third, an agreement to ensure our sanctions efforts disrupt third countries that are supplying Russia's war efforts." 

For his part, Zelenskyy thanked Mr. Biden and Congress for their aid, and offered "thanks to every American heart that does not betray freedom and supports us." 

The security agreement fulfills a pledge last year to solidify Ukrainian security and is meant to be a bridge to an eventual invitation to Ukraine to join NATO. More than a dozen other nations have similar security agreements with Ukraine. 

The president's news conference with Zelenskyy follows a day of meetings with Italian Prime Minister Giorgia Meloni and leaders of the other G7 nations with advanced industrialized economies. 

As Mr. Biden was departing the U.S. for Italy, the Treasury and Commerce departments announced a new round of sanctions targeting Russia and its "war machine." The latest sanctions are aimed at slowing Russia's military growth as it continues its war in Ukraine. The sanctions will make it harder for Russia to import supplies to build military equipment, though they will still allow food and goods to get into Russia outside those sectors. 

The Biden administration is now allowing Ukraine to use U.S. weapons across the border into Russia near the city of Kharkiv, a policy change that the White House says came with Russia opening a new front in its war. 

"Our position here we believe is straightforward and common sensical," national security adviser Jake Sullivan told reporters earlier this week. "Russians are launching attacks from one side of the border directly on to the other side of the border. And Ukraine ought to be able to fire back across that border." 

On Thursday, Mr. Biden said the U.S. stands by its policy of disallowing longer-range U.S. weapons into Russian territory. 

Mr. Biden and Zelenskyy also met last week, on the sidelines of D-Day memorial events in France. Then, Mr. Biden publicly apologized to Zelenskyy for a monthslong holdup in military assistance that allowed Russia to make gains in its war. 

"You haven't bowed down. You haven't yielded at all," Mr. Biden told Zelenskyy in France. "You continue to fight in a way that is just remarkable, just remarkable. We're not going to walk away from you." 

During his press conference with Zelenskyy Thursday, the president was asked if he is satisfied with the justice system, after his son, Hunter, was convicted of felony gun charges this week. Mr. Biden reiterated that he will not pardon his son. 

"I'm extremely proud of my son, Hunter," Mr. Biden said. "He has overcome an addiction. He's one of the brightest, most decent men I know. And I am satisfied that I'm not gonna do anything, I said I abide by the jury decision. I will do that. And I will not pardon him."

Corey Rangel contributed to this report 

Kathryn Watson

Kathryn Watson is a politics reporter for CBS News Digital, based in Washington, D.C.