Secretary of Defense Lloyd J. Austin III put out a statement of gratitude for Slovakia's assistance to embattled Ukraine. 
He applauded the Slovak government's decision to supply an S-300 air defense system to Ukraine. 
"It's a strong testament to how determined Ukraine's neighbors are to help the Ukrainians defend themselves against Russia's unprovoked invasion of their homeland," he said. "We also recognize Slovakia for its extraordinary humanitarian assistance efforts and for hosting thousands of Ukrainian refugees."  
In return for their efforts, the U.S. European Command will reposition one Patriot missile system, manned by U.S. service members, to Slovakia, the secretary said, adding that he expects this battery and its crew to arrive in the coming days.   
The length of their deployment has not yet been fixed, as the Defense Department continues to consult with the Slovak government about more permanent air defense solutions, Austin noted. 
"This deployment of Patriot capabilities to Slovakia aligns perfectly with our previous efforts to bolster NATO's defensive capabilities and to demonstrate our collective security requirements under Article 5 of the NATO treaty. It complements the NATO multinational battlegroup in eastern Slovakia, which includes air defense elements from Germany and the Netherlands, he said. 
The United States will continue to coordinate with allies and partners to support the needs of the Ukrainian military and people, he added. 
Also today, Pentagon Press Secretary John F. Kirby held a briefing for the news media. 
Kirby said the S-300 air defense system that Slovakia is supplying to Ukraine and a Patriot missile system the U.S. is supplying are part and parcel of the larger effort by DOD and allies to bolster NATO's eastern flank and improve deterrence, as well as bolstering Ukraine's defensive capabilities. 
The war in Ukraine now enters a new phase, with a stronger focus by the Russians on the Donbas region in the eastern part of that country, Kirby said. 
The Ukrainians continue to say that one of their most valuable commodities is small arms ammunition. "We and other nations continue to provide literally millions of rounds," he said. 
Kirby has said in the past that several other effective defensive weapons have also been provided to Ukraine by the U.S., including Stinger and Javelin missiles.  
Also, intelligence sharing and communications between U.S. defense and other government officials — including President Joe Biden — and those of Ukrainian officials have been ongoing daily.