Britain warned its citizens traveling to Sweden on Sunday of the possibility of "terrorist" attacks there after incidents of burning copies of the Quran by anti-Islam activists, which angered Muslims.

The British Foreign Office said in updated travel advice that Swedish authorities had successfully thwarted some planned attacks and arrested several individuals.

It also added: "You should remain vigilant at this time... it is highly likely that terrorists will attempt to carry out attacks in Sweden" and that places frequented by foreigners may be potential targets.

Swedish National Security Advisor Henrik Landerholm confirmed in a statement acknowledging the change in British travel advice that threats in Sweden have increased since the incidents of Quran burning.

Landerholm also added that the risk assessment was based on the storming of the Swedish embassy in Iraq on July 19 and the attempted attack on its embassy in Lebanon on August 9, as well as the shooting of an employee at a Swedish consulate in Turkey on the first of that month.

The U.S. government also warned in its travel advice of the possibility of "terrorist" attacks in Sweden.