According to a report by the Syrian Center for Policy Research, over 4,70,000 people have been killed since the conflict in Syria started five years ago. The average life expectancy has also fallen to 56 years from 70. The United Nations had last reported a year and a half ago that 2,50,000 people had been killed in the Syria war.
GAZIANTEP, Turkey — As waves of heavy Russian airstrikes edged closer to the Turkish border on Thursday, a Syrian research group issued a report saying the impact of five years of war in Syria has been more devastating than already thought.
The report from the Syrian Center for Policy Research said that at least 470,000 Syrians had died as a result of the war, almost twice the 250,000 counted a year and a half ago by the United Nations until it stopped counting because of a lack of confidence in the data.
Life expectancy has dropped 14 years, to 56 from 70, since the war began, with an even deeper plunge for Syrian men, says the report, which the group compiled from its longtime base in the capital, Damascus. It put the war’s economic cost at $255 billion, essentially wiping out the nation’s wealth.
The report stood out because it shows a state in collapse in many ways even though it comes from an organization that was, until recently, based in Damascus, the seat of a government that seeks to control tightly how it is portrayed. The report was released on a day that world leaders met in Munich, where the United States and Russia agreed on a cease-fire plan, though it remained to be seen if the parties on the ground would abide by it.
Early Thursday, antigovernment activists and insurgents reported intense Russian airstrikes in the town of Tal Rifaat, the next target for pro-government forces advancing into rebel-held territory in northern Aleppo Province. Video posted online showed clouds of smoke over a jumble of concrete roofs, pancaked houses with their contents spilling into the streets and fighter jets overhead.
The airstrikes on Tal Rifaat, 17 miles south of the Turkish border, came a day after Bouthaina Shaaban, a longtime adviser to President Bashar al-Assad of Syria, told Reuters that Syrian troops would take back control of the Turkish border and reclaim the city of Aleppo. She rejected any talk of a cease-fire as an effort to aid terrorists.
Also advancing on the rebel-held northern countryside of Aleppo were fighters from the Kurdish-led Syrian Democratic Forces, or S.D.F., a coalition the United States is backing to fight the Islamic State.
A group that is part of the S.D.F., called Jaish al-Thuwwar, or the Revolutionaries Army, took Minakh air base, which Islamist insurgents abandoned after Russian airstrikes. There were conflicting reports over whether the S.D.F. forces clashed with the insurgents or simply took ground that they had left undefended.
Those advances created the confusing picture of one American-backed force taking territory from allies of another American-backed force. Minakh was held by Islamist groups that had fought alongside the rebel groups deemed moderate enough to take part in a covert C.I.A. program providing salaries and weapons in cooperation with European and Middle Eastern allies.
That entanglement poses an increasingly thorny problem for Syrian insurgents and the United States, as Russia continues to reserve the right to hit not only Islamic State fighters but any group it sees as hard-line Islamists or that it deems affiliated with them.
Rebel groups accused the Kurdish-led S.D.F. of siding with the government and taking advantage of Russian airstrikes. But the group — dominated by fighters aligned with a Kurdish political party that recently opened an office in Moscow — issued statements saying that it was not working with the government but that it was seizing the land to prevent it from being taken by government forces.
The group told Syrian opposition outlets that it was helping civilians from rebel-held areas to pass through Kurdish-held areas to relative safety. Kurdish groups have generally sought to maintain a détente with all sides, focusing mainly on establishing semiautonomous zones along the Turkish border.
Also on Thursday, Russia accused the United States of bombing a clinic in Aleppo and blaming Russia. An American military spokesman said the allegation was fabricated and that no United States airstrikes had been carried out in Aleppo Province in the last day.
Correction: February 11, 2016
An earlier version of this article misstated the number of years that the life expectancy in Syria has dropped since the war began there, according to the Syrian Center for Policy Research, and misstated the previous life expectancy. It fell 14 years, to 56 from 70, not 20 years, to 56 from 76.
Correction: February 12, 2016
Because of an editing error, an earlier version of this article referred incorrectly to a longtime adviser to President Bashar al-Assad of Syria. The adviser, Bouthaina Shaaban, is a woman.
