(CNN) -- Tar balls found on Florida Keys beaches Monday and Tuesday are not from a massive oil spill off the coast of Louisiana, the Coast Guard said Wednesday.





"A sampling of tar balls discovered on beaches at Fort Zachary State Park, Fla., Smathers Beach in Key West, Big Pine Key, Fla., and Loggerhead Key in the Dry Tortugas National Park, Fla., were flown by a Coast Guard HU-25 Falcon jet based in Miami, Fla., to New London, Conn., Tuesday for testing and analysis," a Coast Guard statement said.





"The results of those tests conclusively show that the tar balls collected from Florida Keys beaches do not match the type of oil from the Deepwater Horizon oil spill in the Gulf of Mexico," the statement said. "The source of the tar balls remains unknown at this time."





However, "the conclusion that these tar balls are not from the Deepwater Horizon oil spill incident in no way diminishes the need to continue to aggressively identify and clean up tar ball-contaminated areas in the Florida Keys," said Coast Guard Capt. Pat DeQuattro, commanding officer of Sector Key West.





DeQuattro authorized the use of the Oil Spill Liability Trust Fund on Tuesday to begin cleanups of any oil pollution on Florida Keys shores and established a unified command made up of members of the Coast Guard, the National Oceanic and Atmospheric Administration, the Department of the Interior, and state and local officials to manage the tar ball response, the Coast Guard said.





The tar balls nevertheless have raised fears that oil from the Gulf spill is headed to the coastlines of Florida and beyond.





Researchers and federal officials seem to agree that a plume of oil is being dragged into the Gulf of Mexico's Loop Current. The current flows through the Yucatan Channel between Cuba and Mexico, and then northward, where it loops just south of the Florida Keys and travels to the west side of the western Bahamas, according to meteorologists.





The European Space Agency issued a statement Wednesday saying satellite images show the oil is in the Loop Current.





"With these images from space, we have visible proof that at least oil from the surface of the water has reached the current," Bertrand Chapron of Ifremer, the French Research Institute for Exploitation of the Sea, said in the statement.





A new tracking forecast prepared by four experts relying on five computer models shows that part of the oil may reach the Keys in five to six days, and Miami, Florida, five days after that, Sen. Bill Nelson, D-Florida, said in a statement Tuesday.





"While I always hope for the best, this is looking like really out-of-control bad," Nelson said.





The forecast cited by Nelson assumes the Loop Current's persistence and does not take into account dispersion and evaporation from the oil spill, CNN meteorologist Sean Morris said. It remains to be seen how much oil has entered the current. In addition, he said, "the Loop Current is much warmer than surrounding water, which would cause oil to evaporate at a greater rate than it is evaporating near the source of the spill."





Also Tuesday, NOAA shut down fishing in a larger part of the Gulf over which the federal government has jurisdiction: a total of 45,728 square miles, which is 19 percent of the Gulf, NOAA Administrator Jane Lubchenco said.





An undersea oil well has been gushing an estimated 5,000 barrels of oil a day (210,000 gallons) into the Gulf since late April, when the drill rig Deepwater Horizon blew up and sank about 40 miles off Louisiana. Some estimates have put the amount of oil spewing from the well far higher.





Eleven workers are missing and presumed dead after the explosion and sinking, and the cause has not been determined.





Samples taken by scientists offshore have raised concerns that large plumes of oil are settling below the surface. But federal officials said the results have not been fully analyzed.





Some of the oil has washed ashore on the Louisiana coast. The Mississippi Emergency Management Agency said Tuesday that the slick was 50 miles off the Mississippi
What does European Space Agency say? What is the group made up of? What was created to manage response to tar balls?
satellite images show the oil is in the Loop Current. members of the Coast Guard, the National Oceanic and Atmospheric Administration, the Department of the Interior, and state and local officials a unified command made up of members of the Coast Guard, the National Oceanic and Atmospheric Administration, the Department of the Interior, and state and local officials
question: What does European Space Agency say?, answer: satellite images show the oil is in the Loop Current. | question: What is the group made up of?, answer: members of the Coast Guard, the National Oceanic and Atmospheric Administration, the Department of the Interior, and state and local officials | question: What was created to manage response to tar balls?, answer: a unified command made up of members of the Coast Guard, the National Oceanic and Atmospheric Administration, the Department of the Interior, and state and local officials