Spies for Vladimir Putin have been working in Nato’s headquarters “for years” the organisation’s general secretary Jens Stoltenberg has said, according to reports.
Russian secret agents were found to be working at the headquarters in Brussels and were removed, Das Bild reported on Saturday.
Mr Stoltenberg told the German tabloid: “We have expelled Russian personnel from Nato headquarters.
"In fact, we found that they were conducting activities that were not actually diplomatic work, but intelligence work.
"The Nato allies have done similar things. This is an issue that is being raised among Nato allies.”
In recent weeks, the threat of Russian spying has become more publicised with German authorities warning Tinder users against going on a date in the country.
Vladimir Putin’s foreign intelligence chief has also visited the pariah state of North Korea to deepen ties between Moscow and Pyongyang.
Mr Stoltenberg added that more would be done to avoid Kremlin espionage.
"We are taking some measures to make it more difficult for Russian intelligence services to carry out illegal activities between or within Nato allies,” he said.
"So as soon as we stand together, we are safe."
Also on Saturday, at least six people died in a drone attack in Kharkiv which saw residential buildings destroyed.
The city’s mayor Ihor Terekhov tweeted: “Kharkiv has experienced a tough night.
“The city was attacked by "shaheds" which struck residential buildings.”
