The NATO on Tuesday launched its "biggest" cyber defense exercise involving more than 700 participants from 25 member states, as well as NATO partner countries, the European Union, industry and academia.
The 3-day exercise, named Cyber Coalition, is managed from the NATO Cyber Range in Estonia, with the majority of the participants taking part from their own workplaces, according to a statement on NATO's website.
"Taking place for the 10th year in a row, Cyber Coalition tests and trains cyber defenders from across the Alliance in their ability to defend NATO and national networks," the statement said, calling Cyber Coalition "NATO's biggest and most important cyber defense exercise".
"The exercise has a challenging, realistic scenario that helps prepare our cyber defenders for real-life cyber challenges," NATO said.
Earlier this month, NATO said it would improve its command structure to tackle modern threats including cyber security.
Speaking at a cyber security conference in Mons, Belgium on Oct. 19, NATO Secretary-General Jens Stoltenberg said cyberattacks were serious, and had the "potential to undermine NATO's missions around the world and to hamper our ability to deliver collective defense".
"That is why cyber defense is a top priority for NATO and for NATO allies," he added.
In September, EU defense ministers, as well as diplomatic chief Federica Mogherini and Stoltenberg took part in a cyberattack readiness exercise in the Estonian capital, Tallinn.
Stoltenberg said there had been a 60 percent increase in the number of cyberattacks against the alliance's networks last year.