WASHINGTON (Reuters) - A U.S. district court issued a preliminary injunction on Monday stopping federal funding of human embryonic stem cell research, in a slap to the Obama administration’s new guidelines on the sensitive issue.

A microscopic view shows smooth muscle cells derived from human embryonic stem cells showing the nuclei (blue) and proteins of the cytoskeleton (green) in this handout photo released to Reuters by the California Institute for Regenerative Medicine, March 9, 2009. REUTERS/Alexey Terskikh/Burnham Institute for Medical Research/California Institute for Regenerative Medicine/Handout

The court ruled in favor of a suit filed in June by researchers who said human embryonic stem cell research involved the destruction of human embryos.

Judge Royce Lamberth granted the injunction after finding the lawsuit would likely succeed because the guidelines violated law banning the use of federal funds to destroy human embryos.

“(Embryonic stem cell) research is clearly research in which an embryo is destroyed,” Lamberth wrote in a 15-page ruling. The Obama administration could appeal his decision or try to rewrite the guidelines to comply with U.S. law.

The suit against the National Institutes of Health, backed by some Christian groups opposed to embryo research, argued the NIH policy violated U.S. law and took funds from researchers seeking to work with adult stem cells.

The U.S. Department of Justice, White House and NIH had no immediate comment.

Key to the case is the so-called Dickey-Wicker Amendment, which Congress adds to budget legislation every year. It bans the use of federal funds to destroy human embryos.

That was not an issue for the NIH until the discovery of human embryonic stem cells in 1998. In 2001, then-President George W. Bush said he could only allow federal research money to pay for work done using a few batches, or lines, of the cells.

Many stem cell researchers objected, saying they could not do work needed to fulfill the promise of the powerful cells, which can give rise to all the tissues and cells in the human body. Privately funded researchers could do as they pleased, but federal funding is the cornerstone of such basic biological research.

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As one of his first acts after taking office, Obama overturned that decision and the NIH set up a careful process for deciding which batches of human embryonic stem cells could be used by federally funded researchers.

The new guidelines do not allow the use of federal dollars to create the stem cells but do allow researchers to work with them if they are made by another lab.

Dr. James Sherley of Boston Biomedical Research Institute and Theresa Deisher of Washington-based AVM Biotechnology, who both work with adult stem cells, filed the original suit saying the guidelines would harm their work by increasing competition for limited federal funding. They both oppose the use of human embryonic stem cells.

Sherley was not immediately available for comment.

“There is no after-the-fact remedy for this injury because the Court cannot compensate plaintiffs for their lost opportunity to receive funds,” Lamberth wrote.

He found that the injunction would not seriously harm researchers who focus on human embryonic stem cells because it would preserve the status quo and not interfere with their ability to get private funding.

With the preliminary injunction in place, the two sides will likely present arguments and case history to the judge over whether the guidelines can be permanently blocked or be allowed to go into effect.