Hundreds of classified NATO files have been leaked online by hackers who accessed the national headquarters of the Portuguese armed forces, media said Thursday.
The Diario de Noticias reported that US intelligence informed Portugal about the unprecedented cyberattack after sensitive information was spotted on sale on the darkweb, the underbelly of the internet.
The US embassy in Lisbon reportedly told Portuguese Prime Minister Antonio Costa about the massive leak in August.
The daily said the US-led military alliance will demand explanations and guarantees from Portugal. The scale of the damage is yet to be established.