A Pakistani military spokesman says his country's nuclear facilities are secure, and that there is "absolutely no chance" that Pakistan's atomic weapons could fall into the hands of terrorists.

Responding to a British researcher's claim that militants have attacked Pakistani nuclear facilities three times since 2007, Major General Athar Abbas said no nuclear weapons were involved in any of those incidents. 

The spokesman in Islamabad disputed the researcher's contention that there is a "genuine" risk of Pakistani nuclear weapons winding up under terrorists' control. 

A scholarly article containing those claims has been published in Britain and the United States, but top U.S. military officials said this week they are "comfortable" that Pakistan's nuclear arsenal is secure.

The article was written by Shaun Gregory, a professor at University of Bradford in Britain who is part of the university's Pakistan Security Research Unit.  It also appeared in a newsletter (Sentinel) published by the U.S. Military Academy in West Point, New York.

The Pentagon spokesman, Geoff Morell, said Tuesday that U.S. Defense Secretary Robert Gates and chairman of the U.S. Joint Chiefs of Staff, Admiral Mike Mullen, are "comfortable" with the security that Pakistan has in place for its nuclear arsenal.

The British article said Taliban militants blew up several entry points in 2008 at an arms factory, Wah Cantonment, that is Pakistan's main nuclear facility, and that two attacks were launched in 2007 against air bases, Sargodh and Kamra, where nuclear weapons are stored.

General Abbas said those attacks did occur, but that they appeared to be aimed at causing bloodshed rather than an attempt to seize military weapons.  He said the three targets in Pakistan have no connection with nuclear weapons production or storage. 

Some information for this report was provided by AP.