GENEVA (AFP) - Switzerland's foreign minister told top diplomats on Monday she favours direct talks with Osama bin Laden to tackle the threat of terrorism. Micheline Calmy-Rey, who has raised both eyebrows and hackles with her controversial style, told Swiss ambassadors gathered in the capital Bern that they needed to talk to "heavyweight political figures" on the world stage even if they are considered persona non grata by other powers. Switzerland does not have any list of banned organisations to which it will not talk, unlike other countries. Calmy-Rey said that groups as diverse as Hezbollah, the FARC guerrillas in Colombia, Tamil Tiger rebels in Sri Lanka and the Lord's Resistance Army in Uganda are all "essential in the search for a resolution" of different conflicts worldwide. She stressed however that any dialogue did not mean "accepting the unacceptable," and conceded that it could sometimes lead to tensions and "complex political blockages". Switzerland has played a high-profile role in negotiations with the FARC in Colombia which has caused strains in its relations with Bogota. Colombian authorities began an inquiry earlier this month into the role of Swiss mediator Jean-Pierre Gontard, suspected by Bogota of handing over a 500,000-dollar (323,000-euro) ransom to the FARC in return for the release of two Novartis employees in 2001. Both Gontard and the Swiss foreign ministry deny the allegation. More than 170 Swiss ambassadors and consular officials are meeting this week in Bern.