Islamabad ? For five years, the Pakistani nuclear scientist lived under virtual house arrest for allegedly leaking atomic weapons secrets to Iran, North Korea and Libya. On Friday, he strolled across the patio of his villa, smiling and waving, and announced to reporters: “I have got my freedom.”

Abdul Qadeer Khan, the father of Pakistan’s nuclear bomb, reached a secret deal with his government that loosened restrictions on his movements.

The decision stirred alarm in Washington, which worries that Iran has continued to pursue nuclear arms and that Pakistan may not be able to safeguard its own arsenal in the face of rising Islamic militancy.

The White House said President Barack Obama wants assurances from Pakistan that Khan isn’t involved in the activity that led to his arrest. State Department spokesman Gordon Duguid said Khan remained a “serious proliferation risk.”

Asked Friday what the international community would think of his release, Khan was typically defiant.

“Are they happy with our God? Are they happy with our prophet? Are they happy with our leader? Never,” he said. “I don’t care about rest of the world. I care about my country. Obama cares about America, not about Pakistan or India or Afghanistan.”

Khan said he had no plans to return to the nuclear field.

His wife told The Associated Press that her husband would remain under some restrictions, including a gag order.

While the 72-year-old scientist is a pariah in the West, he is a national hero for his pivotal role in developing the nuclear bomb for Pakistan and was lionized by Islamists for making it the world’s only Muslim nuclear power.

He was detained in December 2003, however, and admitted on television in early 2004 that he operated a network that spread nuclear weapons technology to Iran, North Korea and Libya.

Khan was immediately pardoned by former President Gen. Pervez Musharraf and placed under de facto house arrest.

Unanswered questions remain about the technology that Khan allegedly shared and with whom he shared it, and whether Pakistani authorities knew what he was doing or profited from sales.

Khan began agitating for an end to the restrictions on him after Musharraf was ousted last year. In recent months, he has been allowed to occasionally meet friends outside his house and has spoken to reporters over the phone.