Beirut, Lebanon (CNN) -- Hezbollah's spiritual leader, Grand Ayatollah Mohammed Hussein Fadlallah, has been hospitalized in Lebanon and is in "critical condition," a source in his office told CNN.
The hospitalization comes after widespread rumors circulating in Beirut that Lebanon's top Shiite leader has been ill and may not live much longer.
Fadlallah was born in 1935 in the Shiite holy city of Najaf, Iraq, and completed his Quranic studies there, according to his website. He has lived in Lebanon since the 1960s and became a spiritual leader of Hezbollah after it was founded in 1982 in response to an Israeli invasion.
In recent years, however, Fadlallah had become distanced from Hezbollah's Iran-influenced leadership.
His views on various topics, including the role of women, are laid out on his website and are considered liberal for a Shiite cleric. But he never swayed from his criticism of Israel.
In a letter penned to President Barack Obama last year, Fadlallah said:
"The size of support and cover-up provided by your country for the Zionist entity has become known. This entity was established on the land whose people were uprooted by the power of iron and fire. The subsequent American policies have contributed to the loss of the Palestinian cause, despite the ratification of many Security Council resolutions."
The United States considers Hezbollah, which has close ties to Iran and Syria, a terrorist organization. The Shiite group is a major provider of social services in Lebanon but also operates a militant wing.
CNN's Nada Husseini contributed to this report.