(Recasts, fresh quotes and details from EU foreign policy chief)

By Michelle Nichols

UNITED NATIONS May 11 (Reuters) - Europe appealed to the United Nations Security Council on Monday to back its plan to stem the deadly flow of migrants across the Mediterranean by dismantling people-smuggling organizations and destroying their vessels, though not by bombing.

European Union leaders agreed last month to "identify, capture and destroy vessels before they are used by traffickers," but it is unclear how that may be achieved and the 28-nation bloc wants U.N. authorization for its operation.

"No one is thinking of bombing. I'm talking about a naval operation," EU foreign policy chief Federica Mogherini said after briefing the Security Council. She said European foreign ministers would meet on May 18 to discuss and set details of the operation.

European members of the Security Council - Britain, France, Lithuania and Spain - are drafting a resolution to approve the European operation under Chapter 7 of the U.N. Charter, which allows the use of force, diplomats said.

The resolution would authorize the EU to intervene on the high seas, in Libyan territorial waters and coastal areas to seize vessels and the draft text is likely to be circulated to the 15-member council in the coming days, diplomats said.

Russia has said any plans to destroy boats used by smugglers would be "going too far." But Mogherini has described her discussions with council members as positive and said she was "quite confident" a resolution could be adopted.

"The crucial thing for the European Union is destroying the business model of the trafficking and smuggling organizations, making sure that vessels cannot be used again," Mogherini said. "They sell hope, but instead of hope they deliver death."

About 1,800 migrants have perished in the Mediterranean this year, the U.N. refugee agency said. Some 51,000 have entered Europe by sea, with 30,500 coming via Italy, fleeing war and poverty in Asia, Africa and the Middle East.

"No refugees or migrants intercepted at sea will be sent back against their will," Mogherini said.

Most of the migrants are traveling to Europe through Libya, which has descended into chaos nearly four years after the fall of Muammar Gaddafi. Two competing governments backed by militia are scrambling for control of the oil-producing country.

Europe wants to win the support of the parties in Libya for its operations. Mogherini said she has spoken with all parties involved in U.N.-led talks.

"All sides in Libya understand that our intention is to work on this with them, in partnership," she said. (Reporting by Michelle Nichols; Editing by Alan Crosby and Richard Chang)