WASHINGTON, Feb 6 (Reuters) - Some newer birth control pills, which carry twice the risk of dangerous blood clots as older contraceptives, should be banned, an advocacy group said in a petition filed with U.S. regulators on Tuesday.

The pills, which include several made by Barr Pharmaceuticals Inc. <BRL.N> and Akzo Nobel NV <AKZO.AS> unit Organon BioSciences, have not been proven any better than some older ones, the Public Citizen petition said.

Blood clots are a known risk of hormonal contraceptives, including birth control pills. They can occur throughout the body and dislodge to block blood flow to the lungs and other crucial organs.

"By banning third-generation oral contraceptives, the FDA will potentially save hundreds of young women a year from developing venous thrombosis and its disabling and sometimes fatal consequences," said the petition, filed with the Food and Drug Administration.

The consumer group estimated that more than 7.5 million prescriptions were filled in the year ended October 2006 for such pills, which also include's Johnson & Johnson's <JNJ.N> Ortho-Cept and Watson Pharmaceuticals Inc.'s <WPI.N> Reclipsen.

Older oral contraceptives contain estrogen and progestin hormones. But newer ones sold in the United States -- so-called "third generation" -- contain a different type of progestin called desogestrel.

The FDA publicly announced the higher blood clot risk in 1995, and newer pills also contain a warning about the risk.

But Public Citizen said its analysis of available research found pills with desogestrel too risky to be sold.

"Since there is no evidence of any superior clinical benefit, it is impossible to recommend that third-generation oral contraceptives remain on the market when second-generation oral contraceptives are equally effective and do not cause an increased risk of blood clots," the petition said.

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