A total of 16,426 women have had the implants removed since investigators found the devices were twice as likely to rupture as rival brands, and that French manufacturer PIP used industrial silicone to fill them, the National Medicines Safety Agency (ANSM) said.

Of the 28,276 implants that have been removed, 7,186, or 25.4 percent, were defective, it said.

Of these, 4,406 showed signs of splitting in the implants' outer skin, and in 1,976 others, illegal gel was "sweating" through it, the agency said.

The ANSM's figures apply only to France. An estimated 300,000 women in 65 countries are believed to have received the implants; some 30,000 of them in France.

News of the faulty implants in 2011 sparked fears worldwide, but health officials in various countries have said the prosthetics were not toxic and did not increase the risk of breast cancer.

The ANSM said on Tuesday that it had found 70 cases of breast cancer among women with PIP implants, "but the detected tumours are not associated" with the devices.

PIP founder Jean-Claude Mas, 73, has been charged with manslaughter and fraud. PIP's implants have been banned and the company, located near Marseille, southern France, has been wound up.