Israeli security sources said that the two detainees are Nazim Abu Salim, the imam of the Shihab Al-Din Mosque in the mixed Arab-Jewish city of Nazareth, and Mohammad Zohadi Naarani. The Nazareth Magistrates' Court has barred the release of any other details.

Police spokesman Micky Rosenfeld said, "All the rest of the details of the case are under a (court) gag order."

According to the sources, Abu Salim is reportedly known for speaking out against Israel and the US from Shihab Al-Din Mosque.

During a 2009 visit to the city by Pope Benedict Abu Slim and others from his Ansar Allah movement hung a banner saying “He is not welcome here.” They also issued statements attacking the pope for comments he made in 2006 depicting Islam as a violent religion.

The sources added that a number of youngsters who prayed at his mosque about two months ago are also suspected of involvement in Al-Qaeda activity.

In June, police and the Shin Bet security agency arrested seven Israeli Arabs from the Nazareth area on suspicion of planning attacks against Jews and Christians.

The suspects, who were arraigned on charges including murder, kidnapping, assault and weapons offenses, were allegedly inspired by the speeches of Al-Qaeda leader Osama Bin Laden.

Local media said the men attended the Shihab Al-Din Mosque. The setting up of the mosque, a makeshift structure of tents, next to the Christian Basilica of the Annunciation in 2000 led to frictions between Muslim and Roman Catholic leaders.

Later in the day the two suspects are expected to attend a hearing at the Nazareth Magistrates' Court on the extension of their remand.

Israel's Arab citizens, who make up nearly 20 percent of the population, are Palestinians who remained in the Jewish state following the 1948 war that attended its creation as well as their descendants.

— With input from agencies