Libya does not want third parties to mediate in the conflict opposing it with Switzerland, says the Swiss foreign minister.
In an interview carried in Saturday's edition of the French-language Le Matin newspaper, Micheline Calmy-Rey said that other parties had tried to mediate but that this had brought "no results".
"From the beginning the Libyans made very clear that they wanted to see this case managed bilaterally, given its family component," she said.
The crisis with Libya was triggered by the detention in Geneva in July 2008 of one of the sons of Libyan leader Moammar Gaddafi, and his wife, on charges of mistreating two of their servants.
Although the servants were compensated and withdrew their charges, Libya has taken a number of retaliatory measures against Switzerland.
These include the detention of two Swiss businessmen, accused of violating visa regulations. Hopes for their release were raised when this year's Swiss president, Hans-Rudolf Merz, went to Tripoli in August and apologised for the arrest.
He believed he was given an assurance that the two men would be released by September 1. However, not only have they not been allowed to leave, but for the last three weeks they have been held in a secret place with no consular access.
Under the agreement Merz reached with the Libyan prime minister, further steps were supposed to be taken which would solve the crisis by October 20.
But according to Swiss media reports, Libya recently refused entry visas to the Swiss diplomats charged with conducting negotiations.
Calmy-Rey would not be drawn on what would happen if the deadline was not met.
"The freedom of two people is at stake," she said. "We must be given time to reflect. And this should be accompanied by silence."
Merz told French-language public radio on Saturday that the date was not important, and that the main thing was to bring the hostages home and normalise relations.
"I am optimistic," he said.
swissinfo.ch and agencies