BEIRUT (Reuters) – Syria agreed to allow the United Nations to inspect the site of a suspected chemical weapons attack from Monday but a U.S. official said it was already too late.

Foreign powers have been searching for a response since many hundreds of people were killed by poisonous gas on Wednesday in the suburbs of Damascus in what appears to have been the world’s worst chemical weapons attack in 25 years.

The United Nations said Damascus had agreed to a ceasefire while a U.N. team of experts are at the site for inspections which will begin on Monday. Syria confirmed it had agreed to allow the inspections.

But there were increasing signs that the United States and its allies were considering taking action, a year after President Barack Obama said the use of chemical weapons was a “red line” that would prompt serious consequences.

A senior U.S. official said there was very little doubt that the Syrian government had used a chemical weapon against civilians on Wednesday and that Washington was still weighing how to respond.

The official also said any decision to grant access to the U.N. inspectors would be “too late to be credible” because evidence had been corrupted by government shelling and other actions.

Keep reading…