Libya's "systematic refusal" to cooperate with Switzerland in the case of two Swiss businessmen who have been prevented from leaving the country for more than a year prompted the decision, a government statement said.

The government said that the two men had been "abducted in violation of international law", and it is not known where they are currently being held. "The Libyan authorities are refusing all visiting rights," the statement added.

Bern may now also seek to restrict visas for Libyan nationals coming to Switzerland.

The dispute stems from the 2008 arrest of the son of Moammar Gaddafi, Hannibal, and his pregnant wife who had come to Switzerland for the birth of their child. Geneva police briefly took the couple into custody on accusations they had abused their domestic staff while staying at a luxury hotel in the city.

The staff were eventually compensated, and the charges were dropped.

Swiss President Hans-Rudolf Merz went to Tripoli in August and apologised for the arrest, triggering heavy criticism at home for doing so. During his visit he signed an agreement to normalise relations with Libya but the deadline for meeting its terms elapsed on October 20.

The Conservative Democratic Party, the Social Democrats and the Greens all welcomed the move to suspend the treaty. Ueli Leuenberger, president of the Greens, hoped ministers had a common strategy for getting the businessmen out of Libya.

No apology

In a separate development, the minister in charge of Geneva police, Laurent Moutinot, said on Wednesday he would not apologise for the arrest, nor would he punish the officers involved because they are innocent.

In a statement, Moutinot said saying sorry would do no good anyway, referring to Merz's apology that to date has proven to have little or no effect.

"One of the reasons why the struggle against domestic violence was too often neglected in the past has precisely to do with the fact that those who do it are strong and the victims are weak," Moutinot wrote. "The state must establish a balance to avoid two-tier justice."

The Libyans were also livid that Swiss media published a picture of Hannibal Gaddafi. Moutinot said authorities were investigating who had leaked the picture and would punish that person "as deserved".

Failed obligations

Wednesday's decision to suspend the agreement further complicates Switzerland's tense relationship with Libya, which retaliated for Gaddafi's arrest by closing Swiss businesses in Libya, withdrawing assets from Swiss banks and cutting off flights between the countries.

When Merz returned from Libya in August after meeting the prime minister, he believed he had received assurances that the two businessmen would be released by the end of the month. The Libyans said that was a misunderstanding and the release never happened.

The agreement the two men signed ncluded a stipulation that an independent tribunal would be set up to look into the circumstances surrounding the detention of Gaddafi and his wife.

Each country appointed a judge to investigate the matter. The two countries were then to jointly appoint a third judge within 60 days from signing the agreement. However, they failed to do so.

swissinfo.ch and agencies