Syria tells civilians to leave Aleppo's Kurdish areas
Thousands have already fled the area following clashes between the army and Kurdish-led forces that have killed more than a dozen people.
The violence comes as the two sides struggle to implement a March deal to merge a semi-autonomous administration and military run by the Kurds in Syria's north into the country's new Islamist government.
Shops, universities and schools were closed for a second consecutive day in Aleppo on Thursday, according to AFP correspondents on the ground.
The violence erupted on Tuesday and have left 17 people dead.
On Wednesday, thousands of civilians fled the two Kurdish neighbourhoods of Sheikh Maqsud and Ashrafiyeh via two corridors set up by the army, which then went on to shell the areas after an evacuation deadline.
On Thursday, the authorities again announced that civilians would be able to leave before 1:00 pm (1000 GMT), with the army warning that it would resume bombardment half an hour after that deadline expired.
'No to war'
A military official on the ground told AFP on Wednesday that the army's operation was "limited" and aimed at "pressuring the Kurdish fighters to leave the area so that the authorities could extend their control over the entire city".
In Qamishli, the main city of Syria's Kurdish areas in the northeast, hundreds of people demonstrated on Thursday against the Aleppo violence, according to AFP correspondents.
"We call on the international community to intervene," said one protester, 61-year-old Salaheddine Cheikhmous. Others held banners that read "no to war" and "no to ethnic cleansing".
UN Secretary-General Antonio Guterres on Wednesday urged both sides to show restraint and swiftly resume negotiations to implement the March agreement, according to spokesman Stephane Dujarric.
In Israel, the foreign minister Gideon Saar condemned what he called "serious and dangerous" attacks against the Kurdish minority.
In July, Israel bombed Damascus during violence between the Islamist authorities and the Druze minority in southern Syria, saying it wanted to protect the community, many of whose members live in Israel.
Turkey, a close ally of the new Syrian government, said it was ready to support the Syrian government in its battle with the Kurdish fighters if Damascus asks for help.