Prominent Sunni Muslim religious commentator Sheikh Yusuf al-Qaradawi charged on Thursday that Shiite Muslims are "invading" Sunni societies.
"I stick to what I have said about an attempted Shiite invasion of Sunni societies," the Egyptian-born cleric, who is based in Qatar, said in a statement.
"We must face up to it otherwise we will have betrayed our mission," Qaradawi added. He also described Shiites as "heretics"
Qaradawi said he was responding to recent criticism by two prominent Shiite clerics, Lebanon's Mohammed Hussein Fadlallah and Iran's Ayatollah Mohamad Ali Tashkiri, of earlier remarks he had made about a Shiite "invasion."
Sunnis represent the majority of Muslims in the Middle East, but Shiites form the majority in Iran and Iraq and have a substantial presence in Lebanon.
Sunni leaders in the region have voiced concern about a Shiite resurgence following sectarian strife between the two communities in Iraq after the overthrow of Saddam Hussein's Sunni-dominated regime in the U.S.-led invasion of 2003 and its replacement by a Shiite-led government.