The Kremlin’s spy chief Sergei Naryshkin warned the U.S. that Ukraine will turn into its “second Vietnam,” amid disagreement in Congress over funding for Kyiv.

“Ukraine will turn into a ‘black hole’ absorbing more and more resources and people,” Russian foreign intelligence chief Naryshkin said Thursday in a written statement published by his agency’s house journal, the Intelligence Operative.

“Ultimately, the U.S. risks creating a ‘second Vietnam’ for itself, and every new American administration will have to deal with it,” he added.

The warning comes after U.S. President Joe Biden on Wednesday urged Congress to further support Ukraine with funding. “We can’t let Putin win,” Biden said.

Biden is trying to push through a $61.4 billion emergency funding request for Kyiv, but opposition against further aid to Ukraine has grown among Republicans in the House of Representatives.

The U.S. was engaged in the Vietnam War — fought between South Vietnam and the U.S. on one side and communist North Vietnam backed by the Soviet Union and China on the other — for nearly two decades. The conflict claimed more than a million lives, including tens of thousands from the U.S., and ended with a comprehensive victory for the North Vietnamese forces.

According to a recent poll, 59 percent of Americans still support sending military aid to Ukraine.