"Ali Hassan al-Jaber has been martyred after his crew was ambushed in the region of Hawari near Benghazi," the television said, without specifying who was behind the ambush or what day it took place.
But the Doha-based channel's director general, Waddah Khanfar, said the killing followed "an unprecedented campaign mounted by the Libyan regime against Al-Jazeera and its employees."
The rebels' February 17 movement, named after the day of their capture of Benghazi, pointed the finger of blame directly at the regime of Libyan leader Moamer Kadhafi.
"Apparently he (Jaber) was followed because the Kadhafi regime has been accusing them," said Mustafa Gheriani, the media organiser at rebel headquarters.
"Kadhafi of course. For the past two days he has been warning that he's going to do something like that. One of our colleagues was with him. One of our people working with Al-Jazeera," he said, when asked who was behind the ambush.
Also in Benghazi, thousands of Libyans took to the streets to pay homage to Jaber and his news channel, which has accused Libyan security agents of jamming its signal, in footage aired by Al-Jazeera.
"The blood of the martyr Ali Jabber will spell the end of the tyrant," read a banner carried by demonstrators.
Al-Jazeera said Jaber, a Qatari national in his 50s, was hit by three bullets and "all attempts to save his life failed." Correspondent Nasser al-Haddar was also wounded "after they came under sustained gunfire," it said.
Al-Jazeera, which has given blanket coverage to revolts in several Arab states since January, vowed it would "not stay silent in the face of this crime and will continue to try to bring the perpetrators to justice" for the killing.
On Thursday, the Brazilian newspaper Estado de Sao Paulo said one its reporters, Andrei Netto, held in Libya since March 2 had been freed by Libyan security forces.
The Estado de Sao Paulo had no information, however, about the fate of a reporter for Britain's Guardian newspaper, Ghaith Abdul-Ahad.
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