A company that claimed it developed a way to harvest stem cells from days-old human embryos without harming the embryos was accused at a Senate hearing Wednesday of misrepresenting its work.

Advanced Cell Technology Inc. of Alameda, Calif., drew fire from Sens. Arlen Specter, R-Pa., and Tom Harkin, D-Iowa., authors of a bill vetoed by President Bush that would have expanded embryonic stem cell research through government funding.

Supporters of such research say it could lead to treatments and cures for a wide variety of ailments, including Alzheimer's and Parkinson's disease and spinal cord injuries.

Bush and abortion foes, however, have opposed embryonic stem cell research because the embryos die in the process of harvesting the stem cells from them.

Advanced Cell Technology said last month it had developed a technique for removing from an embryo a single stem cell that can be developed into a stem cell line without destroying the embryo. The company's claim was echoed in an initial e-mail to reporters from Nature magazine.

Later, however, it was disclosed that the company in its experiments had removed more than one stem cell from the embryos it used, killing the embryos.

Specter, chairman of the Senate subcommittee that decides what health and medical research gets funded, told officials of the company it had not accomplished "what you told the world."

"We have representation which created a lot of hopes ... and now they appear to be dashed," he said.

Harkin, the top Democrat on the subcommittee, said the confusion could have been avoided if the company had acted more responsibly. "This again points out why if we don't do this, you're going to have ... individual companies out there trying to hype things up," he said.

Robert Lanza, the company's vice president for research, defending how it announced the development. "We have developed a technique and we have indeed shown it does work," Lanza said.