Vice President Kamala Harris hailed Poland's compassion in accepting more than one million refugees since Russia invaded Ukraine last month.

Harris made the remarks during a meeting with Polish Prime Minister Mateusz Morawiecki only hours after the US House of Representatives passed a practical spending plan that includes $13.6 billion in aid to Ukraine and its European allies.

The measure appropriates $6.8 billion for refugee care and other economic assistance to allies.

"I've been watching or reading about ordinary people doing extraordinary things, and so I'd like to express our appreciation to you on behalf of the American people," Harris added.

Harris also met with Polish President Andrzej Duda, with whom he was set to hold a news conference in the afternoon. Later that day, the vice president was scheduled to meet with Ukrainian refugees who had fled to Poland after the Russian invasion.

While in Warsaw, the vice president is also set to meet with Canadian Prime Minister Justin Trudeau. Canadian Prime Minister Justin Trudeau has been in Europe recently, meeting with allies to discuss Ukraine.

The White House portrayed Harris' quick tour to Poland and Romania as an opportunity for the vice president to consult with two leaders of NATO's eastern flank members about the mounting humanitarian situation created by Russia's invasion of Ukraine.

Over 2 million migrants have already fled Ukraine — with more than half arriving in Poland — with additional arrivals predicted in the coming days.

However, disagreements between Warsaw and Washington over a Polish plan to transfer Soviet-made fighter jets to a German base for use by Ukraine have placed a pall over Harris' visit to Poland. Shortly after Harris landed in Warsaw late Wednesday evening, the Pentagon firmly rejected the notion.

Poland floated the proposal publicly — without consulting the US — just days after Secretary of State Antony Blinken said the Biden administration was "very, very actively" considering a proposal in which Ukraine's neighbor Poland would supply Kyiv with Soviet-era fighters in exchange for American F-16s.

On the other hand, Polish government authorities insisted that any aircraft transfer take place within the NATO framework.

On Wednesday, the Pentagon ruled out the possibility of NATO jets being transferred to Ukraine, stating that such a move by the US and NATO would pose a "high risk" of worsening the Russia-Ukraine conflict.

General Tod D. Wolters, chief of US European Command, stated Thursday that the "most effective way to assist the Ukrainian military in their fight against Russia is to provide increased quantities of anti-tank weapons and air defense systems." The US and its partners are continuing this endeavor, Wolters noted.

Harris is scheduled to fly to Bucharest on Friday to meet with Romanian President Klaus Iohannis.