The headquarters of the Swedish Security Service in Stockholm was evacuated on Friday, with several people taken to hospital after a possible gas leak.
A perimeter of 100 m around the headquarters was cordoned off and a "handful" of people were taken to hospital, some of whom were police, after detecting an odour at the scene, according to the police web page.
Police later said the cordon had been lifted.
Minister of Justice Gunnar Strommer told TT news agency that the government was following the situation and in contact with the Security Services.
Earlier on Friday, Swedish Prime Minister Ulf Kristersson held a joint news conference with Hungarian counterpart Viktor Orban as the Hungarian parliament is set to ratify Sweden's NATO application next week - the only remaining hurdle before Sweden can become member of the military alliance.

Israeli airstrikes kill eight people on highway south of Beirut
Philippines' Senator says arrest imminent, urges public to block ICC transfer
Israel steps up attacks on Gaza since Iran truce, as military says Hamas rearming
Trump says he does not need China's help to end Iran war
India's Modi cuts size of his motorcade to save fuel, source says
Series of tremors near Tehran renew concerns over major quake risk
Ukraine's Zelenskyy warns of incoming Russian drone attacks during daylight
10 islanders flown to UK for precautionary isolation after hantavirus outbreak
