Government ministers have filed a legal complaint against an unknown person or persons for leaking classified information during a diplomatic crisis with Libya.

Swiss government spokesman André Simonazzi said the cabinet took the step one day after a parliamentary commission decided it was no longer possible to find out who had told the media about secret military plans to extract two Swiss hostages held in Libya. The mission was never carried out.

The cabinet strongly condemned the leaks back in June. Details about the mission had been classified as secret and so leaking them was a criminal offence, Swiss President Doris Leuthard said.

The missions centred on freeing Swiss nationals Max Göldi and Rachid Hamdani, who were arrested in Tripoli in July 2008, days after the arrest in Geneva of Hannibal Gaddafi, a son of Libyan leader Moammar Gaddafi, and his wife, on charges of abusing their staff.

In the row that ensued, Tripoli suspended visas for Swiss citizens, withdrew funds from Swiss banks, stopped oil shipments, reduced flights to Switzerland and detained Hamdani and Göldi on immigration charges that many observers believed to be false.

Hamdani was released in February, but Göldi had to serve a four-month prison sentence, only returning to Switzerland in early summer.