A Senate committee Wednesday approved President Bush's nominee to head the Food and Drug Administration, but a full Senate vote on confirming Dr. Andrew von Eschenbach remained in doubt.

Von Eschenbach overcame earlier holds placed on his nomination by two Democratic Senators pending a recent agency recent decision to allow nonprescription sales of the morning-after pill. But now two Republican senators have vowed to block his confirmation, each for separate reasons.

Sen. Jim DeMint, of South Carolina, wants von Eschenbach to suspend sales of the abortion pill RU-486 and investigate whether it increases the likelihood of infection by a rare but deadly bacterium. And Louisiana Sen. David Vitter wants the FDA to legalize the importation of some prescription drugs from Canada.

Von Eschenbach has headed the FDA on an acting basis for the past year. The agency has been without a permanent head for all but 18 months of the Bush administration.

"We need a strong leader at the FDA right now, one who has a mandate to act," said Sen. Mike Enzi, R-Wyo. "There are many items before the FDA that require the immediate attention of an FDA commissioner vested with full authority. It is time (for) the Senate to move forward with this nomination."

Enzi is chairman of the Senate Health, Education, Labor and Pensions Committee, which approved von Eschenbach's nomination by voice vote Wednesday.