Bulgarian opposition parties demanded Friday that President Georgi Parvanov resign after he had been exposed as a collaborator with the country's communist-era secret service.
A panel dealing with the country's former secret service archives announced Thursday that Parvanov had been recruited on Oct. 4, 1989, just a month before the communist regime in Bulgaria was toppled.
Documents published on the panel's Web site showed that Parvanov went on to collaborate for almost four years.
Parvanov, 50, a historian at a institute for communist party history at the time, has denied being an informer.
But he said last year that while working as a historian he had edited a book and written a review on it for a man who later turned out to be an agent.
The leader of the Democrats for Strong Bulgaria (DSB) party, Ivan Kostov, said in a TV interview that many documents were missing and accused the president of deliberately having ordered files to be destroyed.
In Parliament, floor leaders of three oppositional parties demanded the president resign immediately.
Parvanov's office said the president had nothing to add and had requested that the files said to implicate him be published on the presidency's Web site.
Legislation adopted last December includes no sanctions against those found to be former agents, such as stripping them of public office, but says only that their past be made public.
The commission's report also said that 23 aides of the incumbent and of the two previous presidents, Zhelyu Zhelev and Petar Stoyanov, have been affiliated with the communist secret service.
In April, Bulgaria's parliament elected a panel to open the country's former secret service archives.
The commission is expected to eventually open the files of all public figures - politicians, senior public officials, magistrates and journalists.
Bulgaria, which joined the European Union in January, was one of the last former communist nations to tackle the historical records of its communist past.
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