Iran's senior dissident cleric has been freed after spending five years under house arrest for criticizing the nation's supreme leader, a security official said Thursday.

The hard-line clerics that hold ultimate sway in Iran's Islamic government had been under intense pressure from reformers to free the 81-year-old Grand Ayatollah Hossein Ali Montazeri, who was once set to rule the country and now has become an advocate of change in its political and social restrictions.

The security official said Wednesday that Montazeri was now free to leave his house or receive guests any time he wishes. Ahmad Montazeri, the ayatollah's son, told The Associated Press that his father would meet well-wishers Thursday morning.

The Supreme National Security Council, Iran's highest security decision-making body, ordered the lifting of the house arrest order on Tuesday but apparently delayed implementing the decision because of security and logistical considerations.

The security official, who spoke on condition of anonymity, did not say when the order to effectively lift the house arrest was given.

Security agents who had been guarding Montazeri's home in the city of Qom, the center of Islamic study in Iran, began moving their equipment from a metal outpost guarding the entrance to the home late Wednesday night. Two buses were parked in front of the house to prevent passers-by from watching the movement.

From the outpost, the agents guarded the only entrance to Montazeri's home and monitored all people entering, even his family. Ahmad Montazeri said security agents told him and his family to stay inside the house while they were removing equipment from post.

Iran's Special Clergy Court said the house arrest was lifted because of Montazeri's age and ill health.

Montazeri had been in line to succeed Ayatollah Ruhollah Khomeini, the leader of Iran's 1979 revolution, as Iran's supreme leader. But the pair fell out months before Khomeini died of cancer in 1989 and Montazeri was passed over.

He was confined to his home in Qom, 80 miles southwest of Tehran, since November 1997 after saying the man who succeeded Khomeini, Ayatollah Ali Khamenei, was not competent to issue religious rulings.

Iran's state-run media stripped him of his religious title, describing him as a "simple-minded" cleric, and discussion of Montazeri has been strongly discouraged.

Still, many Iranians have been calling for his freedom. Khamenei, who has the final say on all state matters, apparently approved the decision to lift the house arrest order.

Earlier this month, more than 100 Iranian legislators urged the president, in his capacity as the head of the Supreme National Security Council, to lift the restrictions on Montazeri. Ayatollah Jalaleddin Taheri, a senior reformist cleric, urged Qom religious leaders to intervene for Montazeri. Even hard-line journalists had called for his release, apparently fearing a public relations disaster if he died under house arrest.