Al-Qaeda's affiliate in Syria, Al-Nusra Front, has boosted its presence in the country's divided former economic capital of Aleppo, a monitoring group said on Wednesday, according to AFP.
The Syrian Observatory for Human Rights said Al-Nusra has erected new positions in several districts of the northern city after having sent in a convoy of 200 vehicles loaded with fighters.
The group has deployed in rebel-held eastern Aleppo, said the Britain-based Observatory which relies on a vast network of sources on the ground for its information.
Al-Nusra itself posted on Twitter a video of dozens of four-wheel-drive vehicles transporting gunmen through Aleppo, noted AFP.
"This show of force could signal that Al-Nusra is preparing to take over command of future battles in Aleppo" against government forces, the Observatory said.
The monitoring group's head, Rami Abdel Rahman, said other rebel movements in the city were weakening, among them the Nureddin Zinki group of moderate Islamists that was running out of funds to repair its vehicles or feed its 4,000 fighters.
In addition to fighting the regime of President Bashar Al-Assad, Al-Nusra has also been fighting other rebel groups, most notably the Islamic State (ISIS).
Al-Nusra's reinforcements in Aleppo were dispatched from Idlib province, a bastion of the group in northwest Syria bordering Turkey, the Observatory said.
In mid-January, a security source said pro-regime forces were poised to launch a major offensive to retake Aleppo province and sever supply routes to rebels in the provincial capital.
Much of Aleppo province is held by Al-Nusra and its Islamist allies, or controlled by ISIS jihadists.
AFP contributed to this report.