The Syrian army captured the center of Aleppo, the battle for the largest city is still uncertain

Syrian government forces captured the rebel-held center of Aleppo today after heavy airstrikes over the past week.

State television reported that the army had captured Farfra, near the famous Aleppo fortress, and that clashes were ongoing near the historic core of the city.

Fighting for Syria's largest city and former trading center has been ongoing since rebels seized several neighborhoods in the east of the city in 2012.

Those districts are now under siege and during the past week suffered the heaviest airstrikes since the beginning of the war, in which more than 200 people died and several buildings were razed to the ground, AP reports.

However, the battle for Aleppo is still uncertain. Government forces captured the Handarat area over the weekend, but lost it a few hours later.

In the historic quarter of Aleppo, one of the oldest cities in the world, there is the Umayyad Mosque, which is under the protection of UNESCO. Its 11th-century minaret was demolished during the fighting in April 2013.

And the Syrian Observatory for Human Rights, a London-based organization that relies on information from activists on the ground in Syria, confirmed that government forces are advancing in the historic quarter.

The Observatory said airstrikes in eastern Aleppo killed 11 people and that rebels targeted the nearby government-held villages of Nubal and Zahra, killing a baby.

The latest escalation came after the collapse of a week-long truce brokered by the US and Russia, with the two sides accusing each other of violating the agreement.

A Syrian military official in Damascus said operations in Aleppo would continue "until the terrorists in the eastern parts of the city are wiped out."

Evacuation of the wounded from the eastern parts of Aleppo is urgently needed

The World Health Organization (WHO) and the Red Cross called today for the formation of safe corridors for the evacuation of dozens of sick and wounded from the eastern part of Aleppo, in order to provide them with medical assistance.

The Syrian army launched an offensive on Aleppo last Sunday with the help of Russian air power and Shiite militias, and the WHO says the city currently has only 35 doctors for a population of more than 250.000.

Today, pro-government forces attacked parts of Aleppo controlled by the opposition on several fronts, as part of the largest land offensive to date.

"The WHO is requesting the urgent establishment of humanitarian routes to evacuate the sick and wounded from the eastern part of the city," said WHO spokeswoman Fadela Chaib.

WHO spokesman Tarik Jašarević said that dozens of patients need to be evacuated and that the local health authorities will compile an initial list that will then be given to the Syrian Arab Red Crescent for assessment.

The medical staff in the eastern part of Aleppo is constantly working to save lives, but we are not able to meet the needs for emergency aid and specialists, said the representative of the International Committee of the Red Cross, Krista Armstrong.

"There is a desperate need to evacuate patients, hospitals lack supplies of drugs, equipment and blood for transfusions," she said.

And Syrian doctors announced yesterday that they are in dire need of medical supplies to help the hundreds of wounded. They said that the evacuation of at least 40 wounded is urgently needed.