STOCKHOLM -Swedish Prime Minister Ulf Kristersson condemned "an attempted attack" against the Israeli Embassy in Stockholm, after an object believed to be an explosive device was found outside it and destroyed by the national bomb squad on Wednesday.

Embassy staff had notified police of the object, triggering a large response from law enforcement, Swedish police said.

"This is very serious. An attempted attack on an embassy is an attack both on those who work there and on Sweden," Kristersson said in a social media post, adding police and Sweden's Security Police were investigating "who is or who are responsible".

Kristersson said surveillance of the embassy and of Jewish institutions in Sweden had been tightened.

The device was detonated in a controlled manner, a police spokesperson told the broadcaster TV4.

"We will not be intimidated by terror," Israeli ambassador to Sweden Ziv Nevo Kulman wrote on X.

Police declined to give any detail on the nature of the object, or of how it had gotten into the embassy grounds, and said they had launched an investigation.

The object was believed to be a hand grenade that was thrown over the embassy fence, landing close to the building, daily Aftonbladet reported, citing unnamed sources.

The embassy building was cordoned off at a distance of about 100 metres (yards). REUTERS