TEHRAN Iran's most senior dissident cleric, Grand Ayatollah Hossein Ali Montazeri, has died at the age of 87, providing a fresh catalyst for renewed demonstrations against the country's hardline leadership.
Supporters of Montazeri, an architect of the 1979 Islamic revolution that toppled the U.S.-backed shah, were flocking to the Shi'ite holy city of Qom for the cleric's funeral on Monday, the moderate Parlemannews website said.
Opposition leaders Mirhossein Mousavi and Mehdi Karoubi urged supporters to attend the funeral, declaring Monday a day of national mourning, the reformist Jaras website said.
Riot police were already on the streets in parts of Qom, where Montazeri lived and died, the reformist Tagheer website said. Demonstrations in Qom, the seat of Shi'ite learning in Iran, would embarrass Iran's hardline rulers, particularly if large numbers of Islamic seminary students were to join in.
Montazeri's death from a heart attack, reported by official media on Sunday, coincides with tension rising once again in the Islamic Republic, six months after the presidential poll plunged the major oil producer into political crisis.
"My grandfather died in his sleep last night. People and friends are coming to express their condolences," Naser Montazeri said from Qom, 125 km (78 miles) south of Tehran.
Hundreds of Montazeri supporters took to the streets in his home town of Najafabad, both mourning his loss and chanting slogans, video posted on the Internet showed. Shops in the traditionally moderate town had their shutters down and cloaked in black cloth pinned with pictures of the late cleric.
"Montazeri, congratulations on your freedom," the crowd chanted, and "Dictator, dictator, Montazeri's path will be followed."
Mike Hammer, spokesman for the White House's National Security Council, expressed condolences on the ayatollah's passing, adding: "He was known and internationally respected for his unwavering commitment to universal rights."
Monday's funeral, to start at 0530 GMT at Qom's main shrine, is expected to become a rallying point for the reformist opposition, London-based Iran analyst Baqer Moin said.
"The amount of support shown to him will hearten the opposition who are mourning his loss," Moin said.
The Jaras website said a pro-reform cleric, Ahmad Qabel, was detained on Sunday on his way to the funeral from the northeastern city of Mashhad. He was a student of Montazeri and was traveling with friends and family.
The reports were not possible to verify independently, as foreign media have been banned from reporting on protests and also from traveling to Qom for Montazeri's funeral.
"FRUIT OF MY LIFE"
Montazeri was named in the 1980s to succeed revolutionary leader Ayatollah Ruhollah Khomeini as Iran's top authority, but fell out with him over the mass execution of prisoners.
He spent five years under house arrest until 2002 but remained a leading opposition voice until his death, even though he rarely left his home.
Karim Sadjadpour, associate at Carnegie Endowment for International Peace, said Montazeri was the "religious patron" of the reform movement.
"Given his old age and his isolation he didn't provide strategic leadership to the opposition, but it was far more difficult for the regime to paint the green movement as 'anti-Islamic' when they had Montazeri on their side," he said.
Iran's Supreme Leader Ayatollah Ali Khamenei, who succeeded Khomeini after his death in 1989, expressed his condolences, ISNA news agency reported.
Alluding to Montazeri's dispute with Khomeini, Khamenei said he asked God to forgive Montazeri over a "difficult and critical test" that he faced toward the end of Khomeini's life. Khamenei made clear his opinion that Montazeri failed the test.
Montazeri, who was a close ally of Khomeini before the revolution and jailed several times by the shah's police, was among the government's harshest critics in a clerical establishment where splits have widened since the election.
In August, the ayatollah said on his website that the authorities' handling of street unrest following the election "could lead to the fall of the regime" and he denounced the clerical leadership as a dictatorship.
The pro-reform opposition says the poll was rigged to secure hardline President Mahmoud Ahmadinejad's re-election.
The authorities have denied the charge and portrayed the huge opposition protests after the election, which were quelled by the elite Revolutionary Guards and Islamic militiamen, as a foreign-backed bid to undermine the clerical leadership.
Tension increased earlier this month when pro-opposition students clashed with the security forces armed with batons and tear gas in the biggest anti-government protest in months.
Khomeini once called Montazeri the "fruit of my life," but the official IRNA news agency said "problem elements" in Montazeri's household and his statements "appreciated by enemies of the Islamic Republic" were to blame for his estrangement with Khomeini two decades ago.
(Additional reporting by Hossein Jaseb in Tehran, Alistair Lyon in Beirut; Editing by Jon Hemming)