Analysis: Estonia incident is a major violation - Putin is testing NATO's response
It's clear Vladimir Putin is testing NATO's resilience over its continued violations of member state's airspace, Europe correspondent Alistair Bunkall says.
Three Russian jets were caught flying into Estonia this morning, spending 12 minutes in the country's airspace before being chased away by an Italian policing mission, the bloc reported.
Estonia is the third NATO country to report an incursion of its airspace by Russia in recent weeks, with both Romania and Poland reporting similar incidents.
Bunkall says the incursion into Estonia is Russia's "biggest violation of another sovereign country's airspace so far".
"The Russians very regularly fly close to countries' airspace, including the UK's, and NATO often scrambles fighter jets to shepherd them and to monitor them," he tells presenter Jonathan Samuels.
"But actually flying into a country's airspace - and in this case, the Russian jets were literally flying towards the Estonian capital, Tallinn - that is a major violation.
"It's clearly deliberate and clearly designed to send a form of message to Europe and to NATO."