Aleppo // Fresh fighting hit Aleppo on Thursday, the first day of a promised Russian aid window the UN said was insufficient to bring relief for the Syrian city's desperate residents.
Even as Moscow pledged to pause strikes on rebel-held areas of the city, it carried out raids farther east on the ISIL bastion of Raqqa that killed 24 civilians, according to a monitoring group.
Meanwhile Turkey, which has backed rebel groups against Syrian president Bashar Al Assad, offered Russia the possibility of joint operations against ISIL.
The offer came a day after talks in Moscow between president Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan aimed at ending a crisis in bilateral ties.
A longtime ally of Damascus, Russia has provided air cover for pro-government forces for nearly a year, including in the escalating battle for Aleppo.
The city has been rocked by a recent surge in violence, with residents on both sides of the front line living in fear of being trapped by renewed hostilities.
The United Nations said Russia was considering expanding three-hour pauses in fighting every morning to bring in desperately needed aid.
"Any pause obviously should always be seen and looked at with great interest, because a pause means no fighting, but three hours is not enough," said UN Syria envoy Staffan de Mistura.
Jan Egeland, who heads the UN-backed Syria humanitarian taskforce, said he was "hopeful" talks with Russia could lead to aid entering the city.
But rebels and regime forces clashed in southern Aleppo on Thursday, including during the period when the pause was meant to take hold, said the Syrian Observatory for Human Rights.
Rebels and extremist fighters broke a three-week government siege of the city's east on Saturday, opening a new route for goods through the southern outskirts.
Trucks carrying food were unable to enter the city Thursday because of intense bombardment.
An estimated 1.5 million people live in Aleppo, including about 250,000 in rebel-held districts.
Syria's state news agency said army troops seized territory south of Aleppo on Thursday, adding that rebel fire killed four civilians in a government-held district.
But it made no mention of the "humanitarian windows" announced by Russia.
Fifteen of the only remaining doctors in the eastern half implored US president Barack Obama Thursday to protect civilians from atrocities in their city.
"Unless a permanent lifeline to Aleppo is opened it will be only a matter of time until we are again surrounded by regime troops, hunger takes hold and hospitals' supplies run completely dry," the letter said.
"We do not need tears or sympathy or even prayers, we need your action. Prove that you are the friend of Syrians," they wrote.
Human Rights Watch said on Thursday it had documented six strikes by regime or Russian warplanes on health facilities in the north that killed 17 people in the past two weeks.
"With heavy bombing continuing relentlessly in Aleppo especially, hospitals and clinics need to be treated as the sacred life-saving places they are, not as additional bombing targets," said deputy Middle East director Nadim Houry.
French foreign minister Jean-Marc Ayrault said he was "concerned by reports of a new chemical attack ... that is said to have claimed four lives people and left dozens injured".
Activists accused government forces on Wednesday of carrying out an attack using chlorine gas on a rebel-held residential neighbourhood in Aleppo.
Further east, Russian raids on the ISIL stronghold of Raqqa killed at least 24 civilians and wounded 70 people, said the Britain-based Observatory.
The monitor said another six people were also killed but it had not yet confirmed whether they were civilians or extremist fighters.
Russia said the raids destroyed a "chemical weapons factory" on Raqqa's outskirts as well as a weapons storage facility and ISIL training camp to the north and south-east.
Its defence ministry said the extremist group suffered "significant material damages" in the strikes and that "a large number of fighters have been killed".
A senior Russian senator on Thursday said Moscow was planning to expand its Hmeimim air base on Syria's coast into a permanent facility.
"After its legal status is agreed upon, Hmeimim will become a Russian military base. The appropriate infrastructure will be built and our servicemen will live in worthy conditions," Frants Klintsevich, the deputy head of Russia's senate committee for defence, told
Izvestia
newspaper.
Syria's conflict erupted in March 2011 and has since killed more than 290,000 people and drawn in world powers on all sides of the war.
* Agence France-Presse
