NEW ORLEANS—Media organizations say they are being allowed only limited access to areas impacted by the Gulf oil spill through restrictions on plane and boat traffic that are making it difficult to document the worst spill in U.S. history.

In at least two cases, a media organization and a seaplane pilot say BP PLC -- the company responsible for cleaning up the spill -- appeared to have a role in deciding on access.

Other media, including The Associated Press, have reported coverage problems because their access has been restricted, though not all have linked the decision to BP. Government officials say restrictions are needed to protect wildlife and ensure safe air traffic.

Ted Jackson, a photographer for The Times-Picayune newspaper in New Orleans, said Saturday that access to the spill "is slowly being strangled off."

A CBS news story said one of its reporting teams was threatened with arrest by the Coast Guard and turned back from an oiled beach at the mouth of the Mississippi River. The story said the reporters were told the denial was under "BP's rules."

U.S. Coast Guard and Federal Aviation Administration officials said BP PLC was not controlling access.

Coast Guard officials also said there was no intent to conceal the scope of the disaster. Rather, they said, the spill's complexity had made it difficult to allow the open access sought by the media.

Associated Press Senior Managing Editor Mike Oreskes said the news organization was concerned about the restrictions.

"The Coast Guard obviously has a responsibility to protect natural habitats from both the seeping oil and from excessive traffic," Oreskes said in a statement. "But we have a shared responsibility to keep the public informed about this extraordinary event. It is not the job of either the government or BP to keep journalists from seeing what has happened."

Coast Guard Lt. Commander Rob Wyman said personnel involved in the CBS dispute said no one was threatened with arrest.

Vessels responding to the spill are surrounded by a 500 yard "standoff area" with restricted access, he said.

"If we see anybody impeding operations, we're going to ask you to move. We're going to ask you to back up and move away," he said.

BP contractors are operating alongside the FAA and Coast Guard at a command center that approves or denies flight requests. Charter pilots say they have been denied permission to fly below 3,000 feet when they have reporters or photographers aboard.

Those special flight restrictions, imposed on May 12, cover thousands of square miles of the Gulf and a broad swath of Louisiana's coast. Normally there are no restrictions on flying.