U.S. Secretary of State Rex Tillerson is focusing on strengthening Washington’s “strategic partnership” with Warsaw in meetings with Polish leaders, with security ties and energy cooperation high on the agenda.

Tillerson and Polish President Andrzej Duda met on Friday to discuss a range of issues, including global challenges, regional security and economic prosperity, according to the State Department. 

In Warsaw, Tillerson will also lay a wreath and make remarks at the Warsaw Ghetto Uprising Monument to commemorate the 73rd anniversary of the liberation of Auschwitz.

“The purpose of the secretary’s trip is really to underscore the importance and the deep alliance and friendship that we share with Poland and the Polish people, especially as one of our closest NATO allies,” State Department spokeswoman Heather Nauert told reporters Thursday.

Tillerson’s visit to Poland comes at a time when the United States is boosting exports of American liquefied natural gas (LNG) to central Europe and taking on Russia’s stronghold on energy supplies.

Senior U.S. officials have said Washington will help European nations diversify their energy supply so they will not be solely dependent on Russia.

On June 7, 2017, the first U.S. LNG shipment to Central Europe arrived in Poland. The State Department said at that time Washington “has worked closely with European partners to diversify European energy supplies through new sources of natural gas.”

Tillerson is scheduled to meet with Polish Prime Minister Mateusz Morawiecki and Minister of Foreign Affairs Jacek Czaputowicz on Saturday, before wrapping up his European trip and returning to Washington.

​On Friday, Tillerson met with Ukrainian President Petro Poroshenko on the sidelines of the World Economic Forum in Davos, Switzerland.

The United States has been a stalwart supporter of Ukraine since 2013, when a series of street protests over closer integration with Europe evolved into a major confrontation with President Viktor Yanukovych, culminating in his ouster in February 2014 and leading to a pro-Western government under Poroshenko.

The United States and the European Union have imposed numerous sanctions on Russia over its March 2014 seizure of Ukraine’s Crimean Peninsula and its role in the war in eastern Ukraine.