Several US officials including a senior Republican senator have expressed concern over reports that the Pakistan People's Party chief Asif Ali Zardari, a strong contender for presidency, was diagnosed with mental problems as late as last year, a media report said on Monday.

Though Zardari's spokespersons contend that he had been cured, the American officials were wary of Zardari having a partial control over Pakistan's nuclear arsenal if elected to the post during the September 6 presidential poll, Newsweekreported.

"Typically (the US) would not want that kind of person involved in a nuclear chain of command," said Pete Hoekstra, ranking Republican on the US House Intelligence Committee.

Doctors hired by Zardari had reportedly diagnosed him with mental problems including dementia, depression and post traumatic stress disorder.

Lawyers for Zardari, the report noted, argued in London's [Images] high court he was too ill to testify in corruption-related cases, and they submitted recent mental-health evaluations as evidence.

In March 2007, the Financial Times reported, New York psychologist Stephen Reich concluded Zardari was "chronically anxious and apprehensive" and had thoughts of suicide, though he had not acted on them.

The newspaper wrote that a New York psychiatrist, Philip Saltiel, found that Zardari's long imprisonment in Pakistan while facing corruption probes had left him with "emotional instability" as well as memory and concentration problems.

Reich, said Newsweek, declined to comment.

Two unidentified American officials were quoted by Newsweek as saying Washington regarded Zardari's medical diagnoses as a legal ploy designed to stall corruption cases against him.

Pakistani officials and Zardari supporters said all the allegations against him were trumped up by his enemies, but added, that the prison stresses were real.

In an e-mail to Newsweek, Husain Haqqani, Pakistan's US ambassador, wrote that Zardari "obviously was affected by the torture of imprisonment without conviction. A similar diagnosis is usually made for former POWs immediately after
their release but that does not preclude their full recovery and subsequent running for high political office. Zardari has no current condition requiring psychiatric help or medication."

While Hoekstra told Newsweek that he did not recall being briefed about Zardari's claims of mental incapacity, two other US foreign-policy officials were quoted as saying they found the revelations surprising and disquieting.

But a US official familiar with intelligence, told Newsweek that any elision was unintentional. "No one here should think information was deliberately withheld or suppressed," the official said.

"Nor should they simply accept at face value assertions made with the apparent goal of warding off legal proceedings," the official added.

According to one of the officials, the US government believes Pakistan's nukes are tightly controlled by elite elements of its military and that the nuclear authority of elected officials, including the president, would be "extremely limited."