Fighter jets, aircraft carriers in the Mediterranean, a no-fly zone over Libya and arming the rebels are all options being weighed up by the United States and its allies in the European Union, as a defiant Libyan leader Muammar Gaddafi is continuing to cling onto power and is ordering airstrikes on towns and arms depots.
There appear to be two main options - both would have to be blessed by the United Nations - or NATO.
