Iranian nuclear researcher Shahram Amiri arrived home Thursday, despite efforts by the Central Intelligence Agency to convince him to stay in the U.S., beginning another stage in a saga in which both countries suggest they came out on top.

U.S. officials say Mr. Amiri defected to the U.S. about a year ago and provided valuable information on the country's nuclear program. In return, he was offered the opportunity to resettle and given a $5 million resettlement package to establish his new life in the United States, officials say. CIA officials warned Mr. Amiri that he could face execution if he returned to Iran.

Tehran has cast Mr. Amiri as a victim of U.S. thirst for information about the Iranian nuclear program, which the U.S. says is for weapons development and Tehran says is for peaceful uses. After his disappearance in Saudi Arabia in June 2009, Iran said he had been kidnapped by American agents, a charge the U.S. denied.

After his arrival Thursday, images of a smiling Mr. Amiri at the Tehran's Imam Khomeini Airport holding his son in his arms were broadcast repeatedly through the day on state television channels.

"I was under the harshest mental and physical torture," Mr. Amiri said, according to the Associated Press. He said he was offered $50 million and the opportunity to resettle in the West if he remained outside Iran. A U.S. official called the statement "ludicrous."