Scientists who created a more deadly strain of bird flu have temporarily stopped their research amid fears it could be used by bioterrorists.
In a letter published in two journals, Science and Nature, the researchers have called for an international forum to debate the risks and benefits.
The US National Science Advisory Board for Biosecurity last month asked the authors of the research to omit key details in forthcoming publications.
The panel suggested the data could be used by terrorists.
The BBC reports that biosecurity experts fear an altered, more contagious form of the virus could spark a pandemic deadlier than the 1918-19 Spanish flu outbreak that killed up to 40 million people.
While the H5N1 strain of bird flu is extremely deadly when caught by humans, its impact has so far been limited because it is not easily transmissible between humans.
But the latest joint research, by Erasmus University in the Netherlands and the University of Wisconsin-Madison in the United States, altered the strain and found it was much more easily passed between ferrets.
The Science and Nature journals want to publish the research and are trying to work out with the US government how to make the data accessible to "responsible scientists".