The number of former Guantanamo Bay detainees returning to the battlefield has jumped significantly since last spring, sources with knowledge of the Pentagon's estimates tell Fox News.
Three sources told Fox News that the percentage of released detainees who have either returned to the fight, or are suspected of having returned, has jumped to at least 20 percent in the Pentagon's latest count, from 14 percent in April.
The development comes as President Obama suspends the transfer of Yemeni detainees to their home country in the wake of the attempted bombing of a Detroit-bound flight on Christmas. A Yemen-based offshoot of Al Qaeda claimed responsibility for the plot.
But while the administration continues to face criticism over its plans to close the Guantanamo prison, the president insists he eventually will do so.
Pentagon spokesman Geoff Morrell did not deny claims Wednesday that the recidivism percentage has jumped, but would not directly comment on the updated figured.
"I don't believe the number has reversed itself," he said.
"We're not going to make any decisions that we believe threaten the security of the country," Gibbs said.
Recidivism among the former prisoners has gone steadily up. The April percentage was up from 11 percent in the previous count.
Statistics on Guantanamo detainee recidivism are classified and are only periodically released to the public. Morrell said the Pentagon is working on processing the latest report so it can be released.
A senior administration official told Fox News that the Pentagon was responsible for the timing of the release of the report. The official added that the Pentagon has no evidence that any of the 42 detainees released under the Obama administration have returned to the battlefield against America or its allies.
"We have been presented with no information that suggests that any of the detainees transferred by this administration have returned to the fight," the senior official told Fox News.
Ninety-one Yemenis remain at the facility at Guantanamo Bay, Cuba. Morrell said the decision not to transfer them home "does change the dynamic and it does change the calculation" for the closure of the facility.
Fox News' Catherine Herridge contributed to this report.