The Pakistani leader's pardon headed off a showdown with the political and religious groups which strongly opposed punishment for Abdul Qadeer Khan.

Musharraf accepted the scientist's plea for mercy after he admitted the leaks in a televised apology.

"There's a written appeal from his side and there's a pardon written from my side," Musharraf said at a news conference.

Details of the pardon were not made public, including whether Khan would have to repay any of the money he received for selling Pakistan's nuclear secrets.

Earlier Thursday, the Cabinet had sent a recommendation to Musharraf that Khan be pardoned for the proliferation to the three countries that make up what President Bush (news - web sites) had termed the "Axis of Evil."

In a televised apology Wednesday after meeting Musharraf, Khan accepted full responsibility for nuclear leaks he said were made without government knowledge or approval and asked for forgiveness.

Two weeks ago, Musharraf vowed to move against proliferators he condemned as "enemies of the state," but a decision to prosecute Khan would have outraged many Pakistanis.

On Thursday, Musharraf said he had sought to balance Pakistan's domestic interests and international demands that proliferation activities be brought to light.

"Whatever I have done, I have tried to shield him," Musharraf said of Khan, a national hero. But the president said "one has to balance between international requirements and shielding."

"You cannot shield a hero and damage the nation," the president said.

Musharraf refused to give further details about the pardon, a decision that he said was made on the recommendation of the National Command Authority — which controls the country's nuclear assets — and the Cabinet.

Asked about Khan's motives, Musharraf said: "What is the motive of people? Money, obviously. That's the reality."

He said Pakistan wouldn't submit to any U.N. supervision of its weapons program, and that no documents would be handed over to the U.N. nuclear watchdog, the International Atomic Energy Agency. He also ruled out an independent investigation of the military's role in proliferation.

However, he said the IAEA was welcome to come and discuss the proliferation issue with Pakistan.

"We are open and we will tell them everything," Musharraf said.

Director-General Mohamed ElBaradei, the head of the International Atomic Energy Agency, told reporters before the pardon was announced that it wasn't up to him to comment on "whether he (Khan) would be pardoned apprehended or decorated."

A trial of Khan could have uncovered embarrassing revelations about top government and military officials — amid widespread skepticism about claims that they didn't authorize or know about proliferation of nuclear technology and hardware from tightly guarded facilities to countries where Pakistan had strategic interests.

The president said again on Thursday there was no official involvement in proliferation.

"The reality is that the government is not involved and that the military is not involved," Musharraf said. "It's only the media that are saying this."

In order to become a nuclear power and address the imbalance of military power with rival India, Musharraf said Pakistan had needed people like Khan — who operated covertly from the 1970s until the country's first public nuclear test in 1998.

"In the covert period there was autonomy," Musharraf said. Khan "was tasked to do something and he did it. One could not be that intrusive in case what you desired was not accomplished," he said.

Pakistan began its investigation in November after Iran told the U.N. nuclear watchdog it obtained nuclear technology from Pakistan.

In Vienna, IAEA head Mohamed ElBaradei promised further investigations into the nuclear black market and said experts need to overhaul export controls on nuclear components in light of Khan's admissions.

"Dr. Khan is the tip of an iceberg," ElBaradei said Thursday. "We still have a lot of work to do."

"He was an important part of the process," ElBaradei said. "(But) Dr. Khan was not working alone. There's a lot of chain of activity that we need to follow through on."

Also Thursday, Malaysia said it would investigate a company controlled by the prime minister's son for its alleged role in supplying components to Libya's nuclear program. That company has also been connected to the international nuclear black market tied to Pakistan.