WASHINGTON (CNN) -- Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, is "very alarmed by the growing extremist threat in Pakistan and remains frustrated particularly by the political leadership's inability to confront that threat," his spokesman said Monday.
Adm. Michael Mullen talks to reporters during a visit to Pakistan in February 2008.
Mullen has made two visits to Pakistan in less than three weeks and is "deeply alarmed by what he has found," his spokesman, Capt. John Kirby, told CNN. "It is a very precarious security situation."
Mullen is particularly "alarmed by what is going on the Swat Valley," Kirby said. "Instead of laying down their arms under the terms of a peace deal, the Taliban picked them up."
Mullen is making his views known after returning from his 11th visit to Islamabad over the weekend.
Kirby said the chairman's views about the deterioration in Pakistan have accelerated since he visited Islamabad in early April with special envoy Richard Holbrooke. Watch how Taliban militants have been promoting themselves as Islamic Robin Hoods »
Mullen also reiterated the U.S. offer of any military assistance that the Pakistanis find acceptable, although that does not include U.S. ground troops.
A senior U.S. military official separately told CNN that there is growing worry there are parts of Pakistan's North-West Frontier Province that appear to be under Taliban control and that the Taliban strategy is to maintain governance in those areas.
The U.S. military thinks Pakistan's nuclear weapons remain in safe hands, Kirby said.