Syrian forces and rebels have clashed violently in and around Aleppo as the battle for control of the northern city raged into a third day, with both sides claiming advances.
The Syrian army claimed on Monday to have overrun part of the city's rebel-held Salaheddin district, but the claim was denied by a Free Syrian Army commander.
"The Syrian army took control of part of Salaheddin district and continues its offensive," a security source in Damascus said.
Colonel Abdel Jabbar al-Oqaidi, head of the FSA military council of Aleppo, the country's most populous city and commercial capital, insisted government troops had "not progressed one metre".
"We launched a new assault from Salaheddin during the night, and we destroyed four tanks," the rebel commander said by phone.
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Since the launch on Saturday of the regime assault on Aleppo, the FSA "has already repelled three offensives" against Salaheddin, he said, adding that the rebels controlled "between 35 to 40 per cent of Aleppo".
Rami Abdel Rahman, the head of the Syrian Observatory of Human Rights, said that regime forces were on Monday "just reaching the outskirts of the [Salaheddin] neighbourhood".
Colonel Oqaidi said that "several quarters of Aleppo are being bombed with MiG [fighter jets] and helicopters".
Activists on the ground reported that a string of rebel-held districts in Aleppo were shelled or hit by small-arms fire during the night. They said some were strafed by helicopter gunships.
Outside of Aleppo, rebels seized a strategic checkpoint after a 10-hour battle, securing them free movement between the northern city and Turkey, a FSA commander said.
"The Anadan checkpoint... was taken this morning at [02:00GMT] after 10 hours of fighting," said General Ferzat Abdel Nasser, a rebel officer who deserted the Syrian army a month ago.
By securing the checkpoint, about 5km northwest of Aleppo, the rebels now control a direct route between the Turkish border and the commercial capital.
Six soldiers were killed and 25 were taken as prisoners, General Ferzat said, adding that four of his own men died in the fighting.