US President Joe Biden has lashed out at former President Donald Trump for making a controversial comment about NATO. He has also stressed that his country`s commitment to the alliance is steadfast.

On Saturday, Trump revealed that while he was in office he said the United States might not protect its NATO allies from a potential Russian attack, if they did not pay their fair share of the defense expenditures.

Biden said at a news conference on Tuesday that the former president had sent "a dangerous and shockingly un-American signal to the world."

He said, "No other president in our history has ever bowed down to a Russian dictator." Biden added, "I never will." He said Trump's words were "dumb" and "shameful."

Biden declared, "For as long as I'm president, if Putin attacks a NATO ally, the United States will defend every inch of NATO territory."

Biden stressed that Congress needs to pass a bill to provide urgent funding to Ukraine. A bill has just been approved by the Senate. Biden called on the House of Representatives to approve it swiftly.