Iran accused Britain and other Western nations including France and Sweden of supporting an exiled group that the Islamic state says planned terrorist acts in the country. "The Foreign Ministry summoned the British ambassador to express its harsh criticism over backing of his country and some other Western states of the group that wanted to carry out terrorist acts in the country," IRNA news agency said. Intelligence Minister Heidar Moslehi also named two other European Union nations. "There were some Western countries involved, including Britain, Sweden and France," he told Iran's Arabic language TV station Al-Alam. In London, a Foreign Office spokeswoman dismissed the accusations. "We made clear we condemn all terrorism everywhere," she said. "The government firmly rejects any allegation of British involvement in any such activity." A Swedish foreign ministry spokesman said the matter was being looked into and he had no further comment at this stage. Iran is at odds with the West over its nuclear programme, which the United States and its European allies say is a cover to build atomic weapons. EU members have agreed to push ahead with plans to move beyond the sanctions imposed by the U.N. Security Council last week over the nuclear programme, with extra measures including steps to curb investment in Iran's energy sector. Tehran insists the programme is peaceful. Iran also said on Tuesday it had arrested members of an exiled opposition group who planned to carry out "terrorist activities" in Tehran on the first anniversary of the country's disputed presidential election on June 12. The report said members of the Mujahideen Khalq Organisation (MKO) were arrested by the Intelligence Ministry before they could carry out their plans to detonate bombs in "a few squares in Tehran". In an email to the media on Wednesday, the group denied its members had been arrested in Tehran, saying that "by falsely alleging that those arrested had gone from Iraq to Iran, the establishment was setting the stage for launching an attack on Camp Ashraf" in Iraq, home to several thousand members of the group. Moslehi did not say how many were detained or when. The government said those arrested were trained in Iraq. Iran's presidential election last year was followed by violent street protests, the most serious unrest since the 1979 Islamic Revolution. The opposition says the vote was rigged to secure President Mahmoud Ahmadinejad's re-election. Authorities deny the allegation, accusing the opposition of being part of a Western plot to overthrow the Islamic system.