Samir Allawi, 46, who heads the network's bureau in Kabul, Afghanistan, was arrested Aug. 10 as he prepared to leave Israel via the Allenby Bridge border crossing at the Israel-Jordan border, al-Jazeera said.
Allawi was brought before a military court in the West Bank Tuesday, charged with membership in Hamas and maintaining contacts with the organization's military wing, Haaretz said.
The court extended his remand for an additional 10 days, al-Jazeera said, while Haaretz said he was remanded for an additional week.
Israeli security officials have refused to comment, saying they will respond only when their investigation is complete.
Allawi, who holds a Jordanian passport and Palestinian identity card, arrived in the West Bank three weeks ago to visit his family in the village of Sebastia, near Nablus. He was preparing to return to Afghanistan via Jordan when he was arrested.
Allawi lawyer Salim Waqim told al-Jazeera his client was questioned about his work at the Kabul bureau, and asked to reveal financial information and his ties with colleagues, friends and relatives.
Waqim said Israeli authorities asked for Allawi's computer login information and accused him of membership in Hamas.
Majed Khadr an output manager at al-Jazeera said authorities had asked Allawi to act as an informant, a request he refused.
The Committee to Protect Journalists Monday issued a statement demanding Israel clarify the reasons for holding Allawi. Mohammed Abdel Dayem, program coordinator for the Middle East and North Africa for the New York group, said the organization's "concern for Allawi's well-being and his legal rights is amplified with every passing day that he is held without due process," a statement on the organization's Web site said.