The United States deployed a battery of Patriot long-range anti-aircraft missiles in Lithuania to be used in NATO wargames from Tuesday - the first time the advanced defence system has been brought to the Baltics where Russia has air superiority.
The Patriot battery was brought to the Siauliai military airbase on Monday, ahead of the Tobruk Legacy exercise, and will be withdrawn when the exercise ends on July 22, a Lithuanian defence ministry spokeswoman told Reuters.
The NATO wargames take place ahead of the large-scale Zapad 2017 exercise by Russia and Belarus which NATO officials believe could bring more than 100,000 troops to the borders of Poland and the three Baltic NATO allies - the biggest such Russian manoeuvres since 2013.
Lithuania, Latvia and Estonia possess only short-range anti-aircraft missiles, leaving the skies largely unprotected in the event of hostilities and have expressed concern about their air defence weakness following Russia's annexation of Crimea from Ukraine in 2014.
As a deterrent to Russia in the flashpoint region, the United States has deployed detachments of troops since the Crimea annexation, which have been augmented by four NATO battle groups of more than 1,000 soldiers.
Referring to the NATO exercise starting on Tuesday, Lithuania's Defence Minister Raimondas Karoblis said: "The deployment of Patriots is important because it demonstrates that such moves are no longer a taboo in the region."
"It proves that the missiles can be brought to wherever they are needed, which is very important," he told Reuters.
"Air defence, including ground-based defences, is one of the holes in our defences, and we will not solve it without help from our allies," he said.
The Patriot batteries were used in 200 combat engagements against manned and unmanned aircraft, cruise missiles and tactical ballistic missiles, according to its maker U.S. firm Raytheon.
NATO ally Poland said last week that the United States had agreed to sell it Patriot missile defence systems. In March it said it expected to sign a deal worth up to $7.6 billion with Raytheon to buy eight Patriot systems by the end of the year.