Photo from Syrian opposition's Shaam News Network shows victims of alleged chemical attack by Syrian government.(Shaam News Network/Reuters)

Syrian rebels have accused the government of carrying out a lethal chemical attack near Damascus on Wednesday, targeting areas east of the capital that have a strong opposition presence, the New York Times reports.

Amateur videos posted online showed medics trying to revive people laid out on floors and hospital gurneys with hand-pump respirators, along with images of rooms full of the lifeless bodies. The source of the images could not immediately be verified, and the government of President Bashar al-Assad denied the allegations of a chemical weapons attack.

According to Foreign Policy, Syrian opposition forces are reporting at least 755 casualties: “If that figure is true, what is happening on the outskirts of Damascus today is the worst chemical weapons attack since then-Iraqi President Saddam Hussein unleashed poison gas on the Kurdish town of Halabja in 1988, killing an estimated 5,000 people.”

It’s unclear whether U.N. chemical weapons team, currently in Damascus to investigate a previous alleged chemical attack and given access by the Syrian government to only three sites, will investigate this latest incident.

We’ll update you as we learn more.