Health officials said Monday they have ruled out the abortion pill RU-486 in one of two deaths in women who had taken the drug. The second remains under investigation.

Earlier four women have died of a rare but deadly infection by Clostridium sordellii after undergoing pill-triggered abortions. FDA has warned doctors to watch for infection by the bug. However, the drug, also called Mifeprex or mifepristone, has not been proved to be the cause in any of those cases, the FDA said.

The recent deaths had renewed calls to ban the abortion pill.

Republican Sens. Jim DeMint of South Carolina and Tom Coburn of Oklahoma, urged passage of legislation that would suspend sales of RU-486 after the latest deaths.