UN humanitarian chief Valerie Amos announced the new number yesterday while briefing the Security Council on what she called the "breathtaking levels of savagery" that continue as Syria's civil war enters its fifth year.
The Syrian American Medical Society this month released a report arguing that the UN's estimate of 212,000 people cut off from the outside world was far too low and that the UN was inadvertently underplaying the crisis.
Many aid groups and others in the international community say the divided council has failed the Syrian people on this and other issues. Russia, Syria's ally, has blocked actions such as an attempted referral of the country's situation to the International Criminal Court, though some diplomats say they'd like to try again for a referral.
Syria's conflict started in March 2011 with protests against President Bashar Assad. More than 220,000 people have been killed and almost 4 million people have fled the country since then, while the Islamic State group in the past year has seized parts of the north and east.
Amos on Thursday expressed concern about the fate of the northern city of Idlib, where a consortium of rebels launched an offensive earlier this week.
As the world has taken stock this month of Syria on the anniversary of the conflict, Amos pointed out some of the more grim findings: "Today, a Syrian's life expectancy is estimated to be 20 years less that when the conflict started," she said.
