Diplomatic pressure is mounting to extend a ceasefire in Syria to Aleppo province after more than a week of fierce bombing that has killed hundreds of people there.
Fresh air strikes were reported on Monday, including barrel-bomb attacks outside of the provincial capital.
Russian officials said on Sunday they were calling on the Syrian government to include Aleppo in a temporary truce already in place in Latakia and around the capital, Damascus.
US Secretary of State John Kerry, who arrived in Geneva in an effort to salvage stumbling peace talks, called for a "countrywide" cessation of hostilities.
"We are talking directly to the Russians, even now," Kerry said, after a week in which Moscow refused to rein in its ally, Syrian President Bashar al-Assad.
"The UN Security Council Resolution calls for a full countrywide cessation and also for all of the country to be accessible to humanitarian assistance."
Government forces and rebels are battling each other for control of the city, with each side controlling different neighbourhoods.
As of Sunday, more than 250 civilians, including 49 children and 31 women, had been killed throughout the 10 days of escalated fighting between government forces and rebels, according to the UK-based Syrian Observatory for Human Rights.
The group said 145 civilians were killed in air strikes in rebel-controlled neighbourhoods , while at least 100 civilians "were killed when tens of shells, homemade rockets and explosive cylinders [hit] places controlled by the regime forces in Aleppo".
The Observatory did not identify the warplanes hitting rebel-controlled areas.
|More than 200 civilians have been killed in the last 10 days, according to activists [Abdalrhman Ismail/Reuters]
Local journalist Zouhir Al Shimale said an air strike on the Helluk neighbourhood on Monday injured several people, while at least three people were killed in barrel-bomb attacks in Kafr Hamra in the countryside of Aleppo.
Russia and the Syrian government have said the presence of al-Nusra Front, which was not party to a February 27 ceasefire deal, legitimises the offensive on Aleppo.
Moscow maintained for days that it would not urge Assad's forces to stop air raids but on Sunday, there seemed to be a change in tone.
"Currently active negotiations are under way to establish a 'regime of silence' in Aleppo province," Lieutenant-General Sergei Kurylenko was quoted as saying by Russian news agencies, using a term the Russian and Syrian militaries have used to mean ceasefire.
The Syrian army and the Russian defence ministry said on Monday that the truce around Damascus, which began on Saturday, has been extended for another two days.
Talks in Geneva to agree a lasting, wider ceasefire are in jeopardy as the Syrian opposition says it will leave if the air strikes on Aleppo do not stop.
Al Jazeera's James Bays, reporting from the Swiss city, said both opposition delegates and diplomats were questioning Russia's role in peace efforts.
"Many diplomats will tell you Russia is not properly invested in this political process, that instead it seems they are pursuing or allowing their allies to pursue a military option," he said.
"The process is very close to collapse if they cannot get the cessation of hostilities back in place."
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A Syrian pro-government newspaper said on Thursday the army was preparing an offensive to recapture all of Aleppo and the surrounding province.
Several hospitals in the city have been bombed, drawing international condemnation and intensified calls for a ceasefire.
"Aleppo has been experiencing extreme conflict for four years now and 95 percent of the medical staff in the city has quite understandably already fled," Sam Taylor of the international aid organisation Doctors Without Borders (MSF) told Al Jazeera from Jordan.
"There are only 70 to 80 doctors in Aleppo. That's a ridiculously small amount of medical staff trying to deal with an enormous amount of trauma injuries.
"Hospitals and other civilian infrastructure is not a target in this war. It's appalling that this level of violence still continues in the year 2016."
The Arab League is weighing an emergency meeting to discuss the situation.
State news agency SANA said on Sunday that six civilians were killed and 40 others injured in rebel rocket attacks on the residential neighbourhoods of al-Midan, al-Sulaimaniyah and al-Sayyid Ali.
Source: Al Jazeera and agencies