Tobias Thyberg, who took up the job last Thursday and resigned on Friday morning, had omitted the information during security background checks, the government said. "These are old pictures from an account I previously had on the dating site Grindr. I should have informed about this, but I did not," he told newspaper Dagens Nyheter. Thyberg had been due to be in Norway on Friday with the prime minister for a meeting of northern European leaders, but the adviser's participation was cancelled.  According to information provided to Swedish newspaper Expressen, the government received several images of a sexual nature from an anonymous sender.

It happened shortly after a press release announcing Thyberg taking up the national security adviser job had been issued. On Friday Swedish Prime Minister Ulf Kristersson said that the information should have come to light during the vetting process, according to Reuters. "It is a systemic failure that this kind of information has not been brought forward," Kristersson told reporters in Oslo. The resignation comes just months after Thyberg's predecessor in the high-profile job stepped down and was charged with negligent handling of classified information. Henrik Landerholm announced his resignation in January as police opened an investigation after he allegedly left classified documents in an unlocked safe at a hotel during a conference.

In March Landerholm was charged with careless handling of secret information. Prosecutors said in the indictment that Landerholm had through negligence disclosed "information relating to conditions of a secret nature and whose disclosure to a foreign power could cause harm to Sweden's security". According to Swedish media, his lawyer has previously said that Landerholm believes he is not guilty. (BBC/Reuters)