Warsaw, Poland(CNN) Britain’s Prince William made a rare, unannounced trip to Poland on Wednesday, meeting British and Polish troops stationed near the Ukraine-Polish border and praising their “cooperation in support of the Ukrainian people and their freedom”.

The Prince of Wales first visited the 3rd Brigade Territorial Defense Force base in Rzeszów, where he met Polish Defense Minister Mariusz Blaszczak and toured a display of military equipment.

There he spoke to British and Polish soldiers about the strong camaraderie that has developed since they began working together.

The 40-year-old royal then met with members of the British armed forces to learn more about how they work alongside their Polish counterparts in conducting operations in support of Ukraine.

Upon landing in the Polish capital of Warsaw, William said in a statement it was “fantastic” to be back in Poland.

“Our nations have strong ties. As we work together in support of the people of Ukraine and their freedoms, which are our freedoms and yours, these bonds will be further strengthened,” said the heir to the British throne.

“I’m here because I want to personally thank the Polish and British troops working in close and vital partnership. I also want to pay tribute to the inspiring humanity of the Polish people. You have opened your hearts as well as your homes.” He continued.

“That is why I visited Rzeszów this afternoon, to hear their stories and to recognize their duty. I was impressed by their passion and shared determination to defend our common freedoms,” added William.

This is William’s first trip to Poland since visiting with his wife, Catherine, Princess of Wales in 2017, and the prince is also keen to gain a better understanding of how the country has shown compassion to its Ukrainian neighbours.

After the surprise troop visit, William traveled to Warsaw, where he visited a shelter center “to see first-hand the humanitarian aid and the importance of the support communities across Poland are giving to Ukrainians fleeing the war.”

The facility, described by Kensington Palace as “on the front lines of the humanitarian crisis”, provides shelter for around 300 women and children who have recently arrived in the country and are not yet integrated into local communities.

The former office building-turned-accommodation center is run by the City of Warsaw and opened shortly after Russian troops invaded Ukraine’s borders in an unprovoked invasion.

More than 8 million Ukrainians have fled to neighboring countries since the war began. According to government estimates, at least 1.5 million Ukrainian refugees remain in Poland.

Ukrainian refugees are provided with two meals a day, while a variety of resources – including Polish classes, employment and psychological support, and a children’s play area – are available.

The king was received by the city’s mayor and spoke to some of the displaced Ukrainians living in the center and learned more about how they had moved to Poland.

He also met with volunteers who have been helping those displaced by the conflict to find out how they manage and distribute community donations, which are being spent through a “free shop”.

Williams’ previously unannounced trip to Poland will be a short excursion. On Thursday he will lay a wreath at the Tomb of the Unknown Soldier – a memorial to fallen soldiers on Piłsudski Square in the heart of the Polish capital. Almost 27 years earlier, in 1996, Queen Elizabeth II and Prince Philip laid a wreath at the war memorial during a state visit.

After leaving the tomb, William is due at the Presidential Palace for a meeting with Polish leader Andrzej Duda, where he will “reaffirm the profound relationship between our two nations and underscore my continued support and gratitude to the Polish people.”

He will round off the whistlestop visit by going to a local food hall where he will meet young Ukrainians who will share their experiences of resettlement in Poland after war displacement. They are asked to talk about how they resumed their studies and found a job in Warsaw. The prince will also speak to host families who have helped house Ukrainian refugees, thanking them and their families for opening up their homes and showing their compassion.

The royal family has been unusually open about the war over the past year, offering their support to Ukraine on numerous occasions.

Unlike his mother, who avoided direct statements on political matters during her reign, King Charles III. much clearer on the subject of Ukraine.

“The world has watched in horror at all the unnecessary suffering inflicted on Ukrainians,” the king said in a message last month marking a year since the Russian invasion. “I can only hope that the outpouring of solidarity from around the world will bring not only practical help, but also strength from the knowledge that we stand together.”

Charles previously reiterated his support directly to Ukrainian President Volodymyr Zelenskyy when the two met at Buckingham Palace in early February. As well as the Queen Consort, he has also diaryed engagements with the Ukrainian community in the UK, as have William and Kate.