On Monday, Prime Minister Pedro Sanchez called for an increase in military spending under the banner of Russian "security threat", as Spain approaches 40 years since NATO membership. 

"The war in Ukraine has opened the eyes of European society, including in Spain," said Sanchez at an event at Madrid's Teatro Real, which was attended by King Felipe VI and NATO Secretary-General Jens Stoltenberg.

"Many have understood that our security is no longer guaranteed."

Read more: Global military spending hit new record in 2021

"Today, our security is under threat from the regime of [Russian President Vladimir] Putin," Sanchez said, drawing on the importance of reinforcing "our deterrence capabilities."

That would "require military capabilities that were modern, viable, and deployable, which can only be acquired through increased investment in defence," he said. "The cost of doing nothing would be far higher."

In 2021, Spain invested 1.03% of its GDP in its military - a relatively low figure for a NATO member. Only Luxembourg has a smaller number, according to NATO data. 

The Spanish President vowed to increase military spending to 2% - however, the decision will likely face protest from the far-left coalition partner, Podemos, who refused to join the Monday event.

On June 29 and 30, Spain will host the NATO summit, coming at a time when Sweden and Finland look on to join the alliance, abandoning their military non-alignment stance. Stoltenberg said the event would be "a historic summit". 

"At the Madrid summit, we will chart the way ahead for the next decade," he said, referring to plans to revise and update NATO's military strategy, which was last calibrated in 2010.