White House national security adviser Jake Sullivan said President Biden will continue to push Congress for aid for Ukraine and for a cease-fire in its ongoing war with Russia.

“Our approach remains the same as it’s been for the last two and a half years, which is to put Ukraine in the strongest possible position on the battlefield so that it is ultimately in the strongest possible position at the negotiating table,” Sullivan said Sunday on CBS’ “Face the Nation.”

CBS’ Margaret Brennan asked the adviser if the U.S. has about $6 billion left in approved funding for Ukraine before the money runs out.

Sullivan said Biden made it clear to Ukrainian President Volodymyr Zelensky that he would spend all of the resources passed by Congress “on time and in full.”

That means that by President-elect Trump’s inauguration in January, the U.S. will have “sent the full amount of resources and aid to Ukraine.”

Concerns are growing over what a second Trump term means for Ukraine, as he’s consistently said he would be able to end the war in one day, has highlighted his relationship with Russian President Vladimir Putin and said he would return foreign policy to an America-first agenda.

With his remaining days in office, Sullivan said Biden could appeal to Congress for more aid.

“President Biden will have the opportunity over the next 70 days to make the case to Congress and to the incoming administration that the United States should not walk away from Ukraine, that walking away from Ukraine means more instability in Europe,” Sullivan said.

He also noted concerns stemming from Japan. If the U.S. leaves Ukraine without support, the question about America’s commitment to allies in Asia will also grow, he said.

“President Biden will make the case that we do need ongoing resources for Ukraine beyond the end of his term, because the threat to Ukraine will remain no matter what exactly happens on the battlefield or at the negotiating table,” Sullivan said.