Poland on Monday was set to sign a $2 billion agreement with the United States to provide logistical and technical support for its Patriot missile defense systems, according to Defense Minister Wladyslaw Kosiniak-Kamysz.

Speaking in Krakow, Kosiniak-Kamysz emphasized the significance of air defense as Poland's most substantial military investment to date.

“This is the protection of the Polish sky,” he said in an interview with Polsat, adding that the partnership with the U.S. is a key component in strengthening Poland's national security.

The move follows calls from Prime Minister Donald Tusk for the European Union to establish a continent-wide air-defense shield. The upcoming support and training under the new deal will mark the final stage in making Poland’s Patriot missile systems fully operational.

RTX's (NYSE:RTX) Raytheon unit makes the Patriot missile system, while Lockheed Martin (NYSE:LMT), Boeing (NYSE:BA) and L3Harris Technologies' Aerojet Rocketdyne (NYSE:LHX) are among the companies that supply missiles and components.