This is where Allied forces are deployed across Eastern Europe

NATO has four multinational battlegroups the size of a battalion in Estonia, Latvia, Lithuania and Poland, which operate in rotation. Each is led by the UK, Canada, Germany or the US and includes troops from different member states. The alliance said last month that all four groups are “robust and combat-ready forces”.

Secretary General Jens Stoltenberg has also said he is ready to rapidly further strengthen that presence by sending additional troops and capabilities to the area.

And the NATO deployment is supported by US troops.

The US has its own bases in Lithuania and Romania, along with several in Poland. President Joe Biden last week formally approved the deployment of 3,000 additional US troops to Poland, Germany and Romania, with 8,500 other personnel on extra alert.

NATO has no troops in Ukraine and no plans have been announced to send Alliance troops into the country.

But while Ukraine is not a NATO member, the alliance also provides the country with strategic advice and has described the relationship as “one of NATO’s most substantial partnerships”.

Other assets at the disposal of NATO in the region include a missile defense system in Romania, designed to “detect, track, attack and destroy” ballistic missiles in the atmosphere. A similar facility in Poland will become operational this year.