WASHINGTON  - The Pentagon says Alabama, Florida and Mississippi have requested the federal mobilization of National Guard troops to aid clean-up efforts along the Gulf Coast.

Col. Dave Lapan, a Defense Department spokesman, said Monday that those requests are similar to one made last week by Louisiana. That request allowed up to 6,000 National Guard troops, paid for by the federal government under Title 32 law, to be made available to Louisiana.

So far, on-site coordinators have called in only 600 of those Guard troops, although defense officials say that number could go higher.

Crist says Fla. will send oil cleanup bill to BP

Gov. Charlie Crist says officials don't yet have an estimate of what it's going to cost to clean up Florida's beaches and waters if a massive oil spill reaches the state.

Crist, though, said Monday that Florida would send the bill to the "responsible party" - BP PLC, the oil company that drilled the leaking well in the Gulf of Mexico. Crist said he shared the frustration of local officials who are worried about not having enough floating booms to protect their beaches.

The governor, though, said Florida would "have to do the best with what we have." Crist also signed an executive order declaring a state of emergency in 13 more Gulf Coast counties from Franklin in the Panhandle to Sarasota in southwest Florida.

Sen. Bill Nelson says the oil spill in the Gulf of Mexico could be an environmental and economic disaster for Florida because the state's tourism industry depends on having the beautiful beaches.

The Florida Democrat made the comments before attending a tourism conference in central Florida on Monday.

Nelson added: "We have an ecological and environmental disaster in the making." He says people in Florida's Panhandle are panicked. He said: "They're about to start their tourism season and they're facing the oil spill."

Related: BP says it will pay for Gulf spill's cleanup