What is the main message of the news item? [br] [originaltext] NATO foreign

NATO foreign ministers offered a show of unity in calling for the departure of Libyan leader Moammar Gadhafi, but they ended their meeting in Berlin still apparently at odds over ways to add to their Libyan air operation.
    The leaders of the US, France and Britain published a joint opinion piece in several newspapers Friday saying a future with Mr Gadhafi in power was unthinkable. They said NATO operations must continue so long as the Libyan leader remained in power to protect civilians and keep up the pressure against the Libyan regime.
    NATO Secretary General Anders Fogh Rasmussen reacted to the letter at a final press conference Friday afternoon.
    But only half of the 28 NATO members are actively participating in the airstrikes. France and Britain, which have taken leading roles in the operation, are calling on other NATO members to do more.
    Following talks with Secretary of State Hillary Clinton, British Foreign Secretary William Hague said the two saw "eye to eye" on what was required in the Libya campaign.