Dozens of civilians were among more than 500 people killed since the Syrian Army, backed by Russian airstrikes, started a massive offensive more than a week ago in northern Aleppo province, a monitoring group said Wednesday.
Humanitarian groups warned that healthcare in the beleaguered rebel enclave north of Syria's second city was close to collapse and tens of thousands of displaced people were facing "very precarious conditions."
The Syrian Observatory for Human Rights said 89 civilians, including 23 children, have been killed in Russian airstrikes in the area and in rebel-held eastern Aleppo city since the offensive was launched 10 days ago.
Another 12 civilians were killed in regime-held areas in Aleppo city as a result of retaliatory shelling by rebels, Observatory director Rami Abdel-Rahman said.
The fighting has cost the lives of 274 rebel fighters including members of Syrian al-Qaeda affiliate al-Nusra Front and 143 pro-regime fighters, according to Abdel-Rahman.
With more than 30,000 civilians thought to be displaced between advancing government front lines and the Turkish border, medical charity Doctors without Borders (MSF) said the health system in the area was close to collapse.
"We are extremely concerned about the situation in the south of the district, where medical staff, fearing for their lives, have been forced to flee," said Muskilda Zancada, MSF head of mission in Syria.
Hospitals in the area, including three supported by MSF, have been hit by airstrikes, and some have been completely closed or can only offer limited emergency services, the charity warned.
The Red Cross said that the fighting was putting "enormous pressure" on civilians.
"The temperatures are extremely low and, without an adequate supply of food, water and shelter, displaced people are trying to survive in very precarious conditions," said Marianna Gasser, head of the International Committee of the Red Cross in Syria.
With Russia, the United States and other powers due to discuss the Syrian conflict at a meeting Thursday in Munich, the head of the opposition Higher Negotiations Committee, Riad Hijab, reiterated its demand for an end to sieges and air raids before a planned resumption of peace talks in Geneva.
Suspended last week as the Russian-backed government offensive smashed rebel defensive lines north of Aleppo, the talks are scheduled to restart February 25.
US State Department spokesman Mark Toner said Wednesday it was "very clear what needs to get done" at the Munich meeting: an immediate and credible ceasfire along with full access for humanitarian aid.
"There are very real human stakes on the ground in Syria," he said.
As crowds continued to wait at the closed Turkish border crossing at Bab al-Salameh, Ankara accused Syria and Russia of creating politics aimed at "ethnic cleansing."
The two forces were trying to drive opponents of the Assad regime out of Syria, Turkish Prime Minister Ahmet Davotuglu charged after a meeting with Dutch Prime Minister Mark Rutte in The Hague.
"One goal of the recent attacks in Aleppo is ethnic cleansing," Davutoglu said.
He accused Western countries of hypocrisy for demanding that Turkey open its borders to refugees but doing nothing to stop the Russian attacks that people are fleeing.
The Dutch parliament approved a proposal to take part in the US-led air campaign against Islamic State in Syria. The plan calls for the Netherlands to send four F-16 fighter jets for duty in Syria, initially until July.