A field hospital in Aleppo has become the fourth hospital in as many days to be bombed by the Russian backed Syrian regime.
The Syrian Observatory for Human Rights, a British-based group that monitors the war, reported heavy bombardment by government forces and "back and forth" fighting.
The monitor said warplanes struck a field hospital in the heavily bombed rebel-held al Sakhour district in the second such strike on one of four such medical facilities targeted in the last few days.
The strike caused at least one death and several injuries and put the hospital out of service, the monitor said.
Hundreds of people have been killed in the bombing and many hundreds more wounded, with little access to treatment in hospitals that lack basic supplies.
"They strike without stop. Just look at this crater... We have pulled six bodies and there are still people under the rubble come and see they are all civilians," said Ahmad al Salhi, a rescue worker in Sakhour district said via internet messaging.
The latest strikes come 10 days into a Russian-backed Syrian government offensive to capture eastern Aleppo and crush the last urban stronghold of a revolt against Syrian President Bashar al-Assad that began in 2011.
Russian war planes struck rebel-held areas north of Aleppo as the army shelled the besieged old quarter in a major offensive, rebels and a monitoring group say.
Russia was reported on Friday to be sending more warplanes to Syria to ramp up its air campaign as the United States said it had not yet given up on finding a diplomatic resolution.
Saturday's air strikes focused on major supply lines into rebel-held areas, while fighting raged in the Suleiman al Halabi neighbourhood, the front line to the north of Aleppo's Old City.
Rebels led by the main Islamist rebel group Ahrar al-Sham said on Saturday they had regained several areas in the Bustan al-Pasha district seized a day before, a strategic point north-west of the city.
The army, aided by hundreds of Iranian-backed militias who have arrived in Aleppo, have backed up the air campaign with a ground offensive on several front lines to break rebel defences inside the city.
In a telephone conversation with US Secretary of State John Kerry on Friday, Russian Foreign Minister Sergei Lavrov said Moscow was ready to consider more ways to normalise the situation in Aleppo.
But Lavrov criticised Washington's failure to separate moderate rebel groups from those the Russians call terrorists, which had allowed forces led by the group formerly known as the Nusra front to violate the US-Russian truce.
The United States made clear it would not, at least for now, carry through a threat made on Wednesday to halt the diplomacy if Russia did not take immediate steps to end the violence.
Moscow and Assad spurned the ceasefire to launch the new offensive, potentially the biggest and most decisive battle of the civil war.
Reuters / Newshub.