The Energy Department is developing a new generation of devices to detect nuclear radiation, a capability that the Bush administration views as vital in the battle against terrorism.

Administration officials said Sunday the emphasis on radiation detection has grown in the aftermath of the Sept. 11 attacks and in response to fears that the Al Qaeda terrorist network may succeed in its ambition to obtain either a nuclear device or materials to spread radiation in an urban area.

Several administration officials, speaking on condition of anonymity, said, however, that they knew of no recent indications that Al Qaeda had made any new progress toward obtaining such materials.

The Washington Post reported in its Sunday editions that the administration is alarmed by growing hints of Al Qaeda's progress in this area and that in response the government has deployed hundreds of sophisticated sensors since November to U.S. borders, overseas facilities and sites around Washington.

Sen. Larry Craig, R-Idaho, said radiation sensors were used at the Salt Lake Olympic Games and the Super Bowl in New Orleans.

Research and development of better radiation sensors is being done by the Energy Department's national laboratories, officials said.

The Post report said newer devices for detecting radiation are placed around some fixed points in Washington. It said the devices are called gamma ray and neutron flux detectors that until now had been carried only by members of Nuclear Emergency Search Teams, which are on standby at various locations.

The Post also reported that Delta Force, the elite military unit with anti-terror responsibilities, has been placed on a new standby alert to seize control of any nuclear materials that are detected by the new sensors.

Sen. John McCain, R-Ariz., said Sunday he was unfamiliar with the deployment of newer radiation sensors. He said it is well known that the U.S. government has been concerned for years about nuclear materials falling into the wrong hands — whether it be terrorists or governments hostile to the United States.

"I don't know if the administration has new information or not, but it seems perfectly logical that that would be one of the avenues that a dedicated group of terrorists would pursue," McCain said on CBS' Face the Nation. "But whether they have that capability or not, I just don't know."

McCain noted that searches of Al Qaeda hideouts in Afghanistan by U.S. forces have turned up plenty of evidence that the terrorist network is interested in obtaining a weapon of mass destruction.