The U.S. National Institutes of Health said Tuesday 13 more lines of human embryonic stem cells have been made eligible for federal research funding.

Among the 13 is the one most widely used by researchers, The Washington Post reported. The announcement came as some stem cell research supporters expressed concern the Obama administration was holding back stem cell research, the newspaper said.

NIH Director Francis Collins said researchers would "now be reassured that their research can go forward."

University of Washington Professor of pathology Charles Murry called the announcement "fantastic news."

"Students who were facing the prospects of having to repeat years of work with new lines will now be able to complete their projects as planned," he said.

Murry's research has been on hold while he waited for federal approval to work on one of the lines, the Post said.

The order covers nine lines that had not previously been eligible for federal funding as well as four lines developed by University of Wisconsin researchers that have long been in use, the newspaper reported.

Lisa Hughes, president of the Coalition for the Advancement of Medical Research, said the announcement was "an important step forward."

"This is great news, too, for those in the patient community who continue to wait for better treatments and cures," she said.