President Bashar al-Assad announced plans to seize a key industrial zone in the northern province of Aleppo on Monday, but a group of Syrian opposition activists warned that the assault could not be halted until a solution to the conflict was found.

A statement from the Aleppo Campaign, a group that works to help civilians escape the besieged city, said that the government’s plans to take the industrial zone near the Turkish border in the north of Aleppo were in “direct violation of the Geneva Convention and international law”.

The statement said the Syrian regime’s aim is to “cease the civilian population from entering the industrial area in order to construct a new capital, which would also be used as a military base, and to create a buffer zone around the city”.

It continued: “In addition to the construction of new barracks and military bases, the regime intends to expand the use of the industrial areas as a transit zone and to turn it into a base of operations and a headquarters for its military apparatus and other elements.”

It said the regime would also take control of the main highway that connects Aleppo to Turkey and the nearby town of Akari.

It said that “there are no safe routes for civilians, particularly those living in rebel-held areas of the city”, and that the Syrian government “will continue to use the industrial zones as a way to expand its control”.

The Syrian Observatory for Human Rights, which tracks violence in Syria, said the new plans came after the regime “suddenly” ordered an assault on Akari, with its army “marching towards the area from the east, and a military command to the west”.

The Observatory said government forces were advancing “without any warning”, and said that their “southern front” in the province was also being attacked.

The Observatory did not immediately respond to requests for comment.

A rebel-run media outlet, Dabiq, said an advance team had entered the industrial district.

It said a government fighter was killed.

It added that the army was preparing to enter the industrial districts of Idlib province, where it has previously taken control.

It reported that the city’s main hospital had been attacked, and that residents had been ordered to stay inside their homes.

“The government has intensified its attack on the civilian areas in the industrial sector in order, at the same time, to prevent the civilian populations from escaping the areas,” the DabiQ outlet said.

“This is in direct violation of all international conventions and international laws and will not be allowed to continue.”

The Observatory and DabiQuadrains also reported that a government air force jet had launched “bombardments of a residential area in Idlib”, but that they had no immediate information on the casualties.

It was not immediately clear if the attack was linked to recent clashes between the Syrian army and opposition fighters.

Earlier this week, a rebel group, the Aleppo Media Centre, said government planes had hit two sites in the eastern city of Hama, killing two people and wounding six.

The Syrian Arab Red Crescent said on Monday it had launched an investigation into the reported air strikes in Hama.

A spokesman for the Aleppo Civil Defence, who asked not to be identified, told Al Jazeera that there were no immediate reports of casualties.

Syria’s conflict erupted in 2011, when President Bashar Al-Abadi, backed by Russian air power, declared a “state of emergency” and launched an offensive to retake the rebel-controlled eastern province of Idlib.

In 2014, the conflict escalated to a second round of negotiations between the government and the rebels, with the agreement to halt fighting and return to the negotiating table.

More than 250,000 people have been killed in the conflict, according to the United Nations.