Explained: NATO's presence in Eastern Europe

As tensions with Russia grows, the alliance's presence in the region continues to expand.

Since 2014, when Russia annexed Crimea, NATO has been gradually increasing its military presence in Eastern Europe.

There are now more than 4,000 NATO troops in the Baltic states and Poland, with the alliance also sending extra troops to Ukraine as Russian forces continue to build up on the country's border.

But what is NATO's presence across the wider region?