"We welcome the announcement of military aid with satisfaction because it brings us much closer to peace," Marcin Przydacz, foreign policy advisor to Polish President Andrzej Duda, wrote on Twitter on Monday.
Biden visited the Ukrainian capital under the strictest security precautions on Monday. He and President Volodymyr Zelensky commemorated Ukrainians killed in the fighting.
Biden also announced further military aid for Ukraine and new sanctions against Russia.
The US president travelled on to Poland after Kiev. According to the White House, Biden plans to meet Duda and deliver a speech in front of the Royal Castle in the Polish capital of Warsaw.
Biden also plans to meet representatives of other eastern European NATO countries on Wednesday.
His trip to Ukraine and Poland comes just ahead of the anniversary of the start of the full-scale Russian military invasion this Friday.
