WASHINGTON - Initial stage of an international operation to set up a no-fly zone over Libya "has been successful," said US Chairman of the Joint Chiefs of Staff Admiral Mike Mullen on Sunday.

Speaking to ABC's "This Week" news program, Mullen said with the no-fly zone in place, the government forces' advance on rebel stronghold Benghazi has also been stopped. He told NBC's "Meet The Press" the operation has "limited goals," and isn't aimed at regime change in Libya, but Gadhafi is "going to have to make some choices about his own future" at some point.

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The US military and British forces on Saturday fired over 110 Tomahawk cruise missiles targeting Libya's air defense systems, while French and British fighter jets attacked targets in Libya. US jets later participated in the action, but the scope of US air involvement is unclear at this point. Pentagon has said US forces is providing command and control and logistics, while US airmen and sailors launched electronic attacks against Libyan systems.

Mullen said he is not aware of civilian casualties in the "Operation Odyssey Dawn," which is aimed at preventing "further attacks by regime forces," and "degrade the ability of Moammar Gadhafi's regime to resist a no-fly zone being implemented," according to Pentagon officials.

"Our mission now is to shape the battle space," Vice Admiral William Gortney, director of the Joint Staff, told a Pentagon briefing Saturday. " In such a way that our partners may take the lead."