Opposition-controlled parts of the northern Syrian city of Aleppo came under total siege on Sunday, after government forces seized the only road into the rebel-held area.

"The eastern neighborhoods are now completely besieged," Rami Abdel Rahman, head of the Syrian Observatory for Human Rights told the Agence France-Presse (AFP) news agency on Sunday.

He said regime forces, along with fighters from Lebanon's Hezbollah group, descended on the strategic Castello Road route and completely cut it.

Castello Road is the only highway leading into and out of rebel-held parts of Aleppo. Analysts say its capture has left hundreds of thousands of people trapped, raising fears of a humanitarian crisis.

The road had been used by rebels, but also by shopkeepers bringing in produce for residents and by villagers visiting relatives in the city.

AFP reported that its capture was confirmed by a rebel fighter from the Aleppo Revolutionaries group, who said: "The army has reached the road and even arrested a group of civilians who were walking there."

Violence sustained

An Aleppo-based activist told The Associated Press (AP) news agency that the city is being subjected to intense shelling and airstrikes.

Another activist Bahaa al-Halaby told the AP that as of Sunday, food and medical supplies will not be able to reach rebel-held parts of the city and seriously wounded people could not be evacuated for medical treatment.

Although Aleppo has not been declared as besieged by the United Nations, residents have complained of food shortages and skyrocketing prices. Shopkeepers have begun rationing their products and there have been long queues outside bakeries.

Victory for regime

The capture of Castello Road marks the biggest success for the government in Aleppo since rebels seized parts of the northern city in the summer of 2012. The government controls the west, while the east is under rebel command.

On Saturday, at least 28 civilians including children were killed in the bombardment of the eastern districts, according to the Observatory, while another four people died in rebel rocket fire on the government-controlled neighborhoods, it said.

Once Syria's commercial powerhouse, Aleppo has seen intense fighting in recent months, with Syrian troops and their allies advancing with the aid of Russian airstrikes.

Earlier this year the government launched a wide offensive that captured much of the city's northern outskirts. Last month, the self-proclaimed "Islamic State" (IS) group withdrew from the area after a month-long siege of rebel-held areas.

mm/jlw (AFP, AP, Reuters)