"I want to emphasise the unity of the North Atlantic Alliance," Andrzej Duda told reporters after the online meeting late on Monday, amid a standoff between Russia and the West over Kyiv's NATO ambitions.
"There is no ally at the moment that would break the solidarity with Ukraine, with the rest of NATO," the Polish president added.
Duda said the meeting with Biden focused on "the situation around Ukraine, but also the entire eastern flank of NATO."
He announced a plan to convene a meeting of Poland's National Security Council on Friday to discuss tensions with Russia over Ukraine.
'Joint efforts to deter further Russian aggression': Biden
Meanwhile, Biden said in a Twitter post that he "spoke with European leaders in response to Russia’s military buildup on Ukraine’s borders."
He added: "We discussed our joint efforts to deter further Russian aggression, such as preparations to impose severe economic costs on Russia and reinforce security on the eastern flank."
The White House later said in a statement that Biden "held a secure video call with European leaders" and that those taking part "reiterated their continued concern about the Russian military build-up on Ukraine’s borders and expressed their support for Ukraine’s sovereignty and territorial integrity."
According to the statement, the "leaders underscored their shared desire for a diplomatic resolution to the current tensions and reviewed recent engagements with Russia in multiple formats."
The leaders "also discussed their joint efforts to deter further Russian aggression against Ukraine, including preparations to impose massive consequences and severe economic costs on Russia for such actions as well as to reinforce security on NATO’s eastern flank," the White House said in its statement.
"They committed to continued close consultation with transatlantic Allies and partners, including working with and through the EU, NATO, and the OSCE," it added.
The White House also said that participants in the call included European Commission President Ursula von der Leyen, European Council President Charles Michel, French President Emmanuel Macron, German Chancellor Olaf Scholz, Italian Prime Minister Mario Draghi, British Prime Minister Boris Johnson, and NATO Secretary-General Jens Stoltenberg, in addition to Poland's Duda.
'Any further aggression' by Russia 'will have severe costs': NATO chief
NATO's Stoltenberg tweeted after the call: "Great meeting with the president of the United States on European security with NATO leaders Emmanuel Macron, Olaf Scholz, Mario Draghi, Andrzej Duda, Boris Johnson and our EU partners: European Council President [Charles Michel] and European Commission President] Ursula von der Leyen."
He added: "We agree that any further aggression by Russia against Ukraine will have severe costs."
Earlier on Monday, the Polish president's national security adviser, Paweł Soloch, told reporters that Poland was yet to make a decision on military assistance to Ukraine, but would not be sending troops to its eastern neighbour for now.
Soloch, who heads Poland's National Security Bureau (BBN), made the statement after the Polish head of state met with senior Cabinet ministers to discuss the situation surrounding Ukraine, news agencies reported.
Duda on Monday spoke with Defence Minister Mariusz Błaszczak and Interior Minister Mariusz Kamiński, as well as senior military and security service officials, his office said in a statement.
NATO said on Monday it was putting forces on standby and sending additional ships and fighter jets to eastern Europe in a move aiming to reinforce deterrence and defence as Russia continues its military build-up in and around Ukraine.
Source: PAP, whitehouse.gov, Reuters