The Senate, weighing legislation designed to cope with the rising costs of prescription medicine, signaled support Wednesday for the idea of forcing drug manufacturers to reduce their U.S. prices to what they charge overseas.

In a pair of votes on amendments, the Senate decided 99-0 to require the secretary of Health and Human Services to certify that importation of generic drugs would pose no significant safety risk and would result in significant savings.

Separately, senators voted 69-30 to allow the secretary to block that supply line if evidence develops which shows that consumer safeguards are insufficient.

A more sweeping amendment to the legislation written to ease public access to generic drugs likely will be approved Thursday. That provision would allow drugstores and medical distributors to buy U.S.-made drugs in Canada, where they are cheaper, and resell them in the United States.

For some time now, many lawmakers and health-care groups have complained that drugs are cheaper across the border in Canada -- and thousands of older Americans have traveled there by bus to drive home the point.

The bill's goal "is to try to force a repricing of prescription drugs in this country," said Sen. Byron Dorgan, D-N.D., one of the measure's sponsors. "The American consumer is charged dramatically more for the same prescription drug. It's unfair."

Democrats had initially opposed the HHS certification provision, offered by Sen. Thad Cochran, R-Miss., arguing that it would weaken the bill. But Cochran said that without the certification provision, "There's no guarantee of their safety or efficacy."

Lawmakers were still gridlocked over several competing plans to add a prescription drug benefit to Medicare. None of the plans has the 60 votes needed for passage.

Off-the-floor talks center mostly on a plan offered by Senate Democrats that would cost up to $500 billion over 10 years and a $370 billion plan offered by a tripartisan group of Democrats, Republicans and an independent.

In a sign that Democrats were willing to make changes, Senate Majority Leader Tom Daschle, D-S.D., said he would be "flexible" despite his support for the Democratic bill.

"I'm really not interested in drawing any hard lines in the sand here," Daschle said. "I think that there is a real possibility that some compromise is within our grasp."

Meanwhile, Senate Democrats prepared to release a report Thursday that gives a state-by-state look at how senior citizens would fare under the Democratic plan and competing proposals.

According to the Democratic report, a copy of which was obtained in advance by The Associated Press, 30 percent of Medicare beneficiaries would have to pay premiums and high drug costs while not receiving benefits because of a gap in coverage in the tripartisan proposal.

Democrats say their plan is superior because it's more generous and has no gap in coverage. Republican have complained that it's too costly.