TEHRAN (Reuters/AFP) - A powerful Iranian cleric suggested on Friday that detained local staff from the British Embassy in Tehran would be put on trial in the Islamic Republic for their alleged role in post-election unrest. In London, British Foreign Secretary David Miliband said he was urgently seeking clarification of Ayatollah Ahmad Jannatis statement. Britain also said it was very concerned about the Iranian clerics threat. In these developments their embassy here maintained a presence (in the unrest) in which individuals were arrested and inevitably they will be tried as they have (made) confessions, Jannati said in his Friday prayers sermon in Tehran. The cleric reiterated accusations by other senior Iranian figures that the West had planned a so-called velvet revolution to undermine the Islamic Republics establishment. They (the British) had ahead of time ... announced that in the election that is scheduled to take place in Iran there might be unrest and turmoil, he said. Reacting to Jannatis remarks, British Foreign Secretary David in a statement, We have noted the remarks by Ayatollah (Ahmad) Jannati suggesting that some of our local staff in Iran may face trial. We are urgently seeking clarification from the appropriate Iranian authorities. I intend to speak to FM (Manouchehr) Mottaki. We are confident that our staff have not engaged in any improper or illegal behaviour. We remain deeply concerned about the two members of our staff who remain in detention in Iran. The British Foreign Office said, We are concerned and we are checking the reports, a spokeswoman said. Allegations that our staff were fomenting unrest are wholly without foundation. The EU nations summoned Iranian ambassadors in protest over the detention of British Embassy employees, a source close to the Swedish EU presidency said. We are summoning the Iranian ambassadors throughout the European Union and we will be monitoring the situation next week concerning the local personnel from the British embassy, the source told AFP. All options remain open, he added. The summoning of ambassadors and charge daffaires is happening during the day, some have already summoned the envoy there, another diplomat said. A total of nine local staff at the British Embassy in Tehran were initially arrested late last month but the British government said seven have been released, while Iranian state television has said only one remains in custody. Iran accuses the British embassy employees of instigating riots in unrest that erupted over the disputed re-election of President Mahmoud Ahmadinejad, which his rivals say was fraudulent and marred by widespread irregularities.