Seven US F-15C Eagle jet fighters and 140 airmen have arrived in NATO-member Lithuania where they formally took over the NATO Baltic Air Policing Mission from Poland. The US aircraft from the 48th Fighter Wing, based at RAF Lakenheath in the UK, will patrol the Baltic airspace alongside Belgian Air Force F-16s that are deployed to Estonia.
This is the first time the US has taken over the policing mission, which rotates between different NATO members, since January 2014 and it comes as Russia is gearing up for a major military exercise, Zapad 2017, which is expected to involve tens of thousands of troops participating in war games in the region.
"Today we are particularly grateful to Poland and the US who have sent their troops to the NATO Baltic Air Policing Mission. The US and Poland are the closest allies of Lithuania and therefore their robust support and determination to enhance the security measures and safeguard our skies are extremely valued by every Lithuanian citizen. Our people know that all alliance is and will be here in all domains if need be," Lithuania's Vice Minister of National Defense Vytautas Umbrasas said at a ceremony commemorating the transfer of command.
The US aircraft will be patrolling airspace that has grown increasingly congested in recent months.
NATO officials have acknowledged an increase in the number of intercepts of Russian military aircraft.
"We have seen an increase in air activity in the Baltic region," NATO Secretary General Jens Stoltenberg told reporters last month following a meeting of the NATO-Russia Council. He also referred to a Finish Initiative which recently convened a working group of representatives from Russia, NATO, Sweden and Finland to discuss the issues involving the congested Baltic airspace.
But the increase in US military presence in the region comes as Russia is gearing up for its major military exercise, Zapad 2017, which is expected to involve tens of thousands of troops operating along NATO's borders in Western Russia, the Russian European enclave of Kaliningrad and Belarus.
Military analysts see such war games as a possible rehearsal for a Russia-NATO armed conflict as it is taking place very close to an area that analysts consider to be the most likely target of a Russian offensive.
ZAPAD 2017 has also sparked concerns among NATO's easternmost members that Russian forces may stay in the area following the conclusion of the exercise.
Russian officials have said that only 13,000 troops will participate but western observers have said that as many as 100,000 Russian and Belorussian forces could be involved.
NATO has also been critical about how transparent Moscow has been about Zapad 2017, saying it has failed to adhere to international treaties by not allowing observers to monitor the exercise to ensure that it is not a cover for an aggressive military operation.
NATO spokesperson Oana Lungescu told CNN Wednesday that Russia and Belarus are avoiding "mandatory transparency" with regard to inviting international observers to monitor Russia's upcoming massive military exercise.
The western alliance acknowledged that Russia and Belarus have invited three military representatives to attend a "Visitors' Day" but NATO says this "falls short" of what is required by the Vienna Document, referring to the agreement that governs military exercises.
"A Vienna Document observation involves required elements: briefings on the exercise scenario and progress; opportunities to talk to individual soldiers about the exercise; and overflights of the exercise," she said, adding "Russia and Belarus are instead choosing a selective approach that falls short. Such avoidance of mandatory transparency only raises questions about the nature and purpose of the exercise."
On Monday, NATO declared its four multinational battle groups in Estonia, Latvia, Lithuania and Poland, involving some 4,500 troops, "fully operational."
The battle groups were established following Russia's 2014 military seizure of Crimea.
"The four battle groups are one part of the Alliance's response to Russia's use of force against its neighbors and its military build-up in the Baltic region and beyond," NATO said in a statement following the units being declared fully operational.