The US food safety authority on Tuesday approved meat and milk from cloned animals, clearing the way for them one day to appear on store shelves despite opposition on ethical and health grounds.
"Meat and milk from clones of cattle, swine, and goats, and the offspring of clones from any species traditionally consumed as food, are as safe to eat as food from conventionally bred animals," Food and Drug Administration (FDA) official Randall Lutter told a news conference.
Lutter said his agency would not require food made from cloned animals or their offspring to be specially labeled, but producers could apply for the right to label their foods "clone-free."
The FDA however said it did not have enough information to rule on whether cloned sheep and other cloned animals were safe to eat.
The agency unveiled an advisory report based on six years of risk assessment studies to decide whether to give the green light for marketing foods from clones.
The ruling was delayed by strong resistance from food safety and animal rights groups, as well as the US dairy industry, which fears its image and exports will be damaged.
The US Department of Agriculture (USDA) said cloned animal foods should not be marketed for the time being, pending consultations on introducing them.
"USDA is encouraging the technology producers to maintain their voluntary moratorium on sending milk and meat from animal clones into the food supply during this transition time," USDA official Bruce Knight told reporters.
The European Commission has vowed to consult consumers before giving its own ruling in May. The European Food Safety Authority said meat and milk from healthy cattle and pig clones is probably safe for humans to eat.
A Washington-based campaign group, the Center for Food Safety, condemned Tuesday's announcement.
"The FDA's bullheaded action today disregards the will of the public and the Senate -- and opens a literal Pandora's Box," the group's director Andrew Kimbrell said in a statement.
"FDA based their decision on an incomplete and flawed review that relies on studies supplied by cloning companies that want to force cloning technology on American consumers."
US senators last month passed a farm bill that included a measure requiring the FDA to delay its ruling until further studies are carried out.
One of the sponsors of that measure, Maryland Senator Barbara Mikulski, accused the FDA of acting "recklessly" on Tuesday.
"Just because something was created in a lab, doesn't mean we should have to eat it," she said in a statement.
"If we discover a problem with cloned food after it is in our food supply and it's not labeled, the FDA won't be able to recall it ... the food will already be tainted."
More than 60 percent of Americans believe it is morally wrong to clone animals, according to a 2005 Gallup poll.
The cloning industry welcomed the news. Biotechnology Industry Organization (BIO) chief Jim Greenwood in a statement hailed what he called the FDA's "comprehensive scientific review."
"Livestock cloning is the latest step in a long history of reproductive tools for farmers and ranchers, and can effectively help livestock producers deliver ... high-quality, safe, abundant and nutritious foods," he said.
It will still be years before meat and milk from clones appears in US stores, reports say. The animals involved, clones of the highest quality beasts, are too valuable to slaughter or milk and better used for breeding.
"Clones are intended to be used as elite breeding animals to introduce desirable traits into herds more rapidly than would be possible using conventional breeding," the FDA said in its report.
Major US pork processing firm Smithfields said it did not plan to produce meat from cloned animals.
"The science involved in cloning animals is relatively new," the company said in a statement. "We will continue to monitor further scientific research on this technology."
BIO, which represents leading cloning companies including key player ViaGen Inc., last month launched a registration system to track cloned livestock throughout the food processing chain.
It said the program would address market concerns when the voluntary moratorium is lifted.