(CNN) — U.S. Secretary of State John Kerry, speaking Sunday from Paris, where he met with Arab League ministers, said the group unanimously condemned a reported chemical weapons attack last month by the Syrian government.
“As we discussed today, all of us agreed — not one dissenter — that (Syrian President Bashar) al-Assad’s deplorable use of chemical weapons — which we know killed hundreds of innocent people, including at least 426 children on this occasion, this one occasion — this crosses an international, global red line,” he said.
He said the foreign ministers discussed the “possible and necessary measures” needed to deter al-Assad from using chemical weapons again. Kerry said a “number of countries immediately signed on” to an agreement reached by 12 countries on the side at the recent G-20 summit.
The Syrian government has denied being behind chemical weapons attacks, which it blames on rebels.
Videos that purport to show the results of a chemical weapons attack on August 21 are part of a White House campaign to inform Congress about the nature of the incident, Kerry said.
“The reason for this is to make sure everybody understands what is at stake,” he said. “Those videos make it clear to people that these are real human beings, real children, parents being affected in ways that are unacceptable to anybody, anywhere, by any standard.”
Kerry met for three hours with the foreign ministers.
Kerry will also meet with UK Foreign Secretary William Hague in London. Britain’s Parliament has ruled out getting militarily involved in Syria, but Prime Minister David Cameron has pledged to continue to push for a tough response against the al-Assad regime.
Kerry’s efforts with European allies paralleled those of his boss, U.S. President Barack Obama, who tried to rally members of the G-20 in St. Petersburg, Russia, last week.
Obama met with his Russian counterpart, President Vladimir Putin, on the sidelines of the St. Petersburg summit Friday. But despite both saying the talks were constructive, there was no sign of consensus.
International opinion remains divided on what should be done after the Syrian government allegedly used chemical weapons against its own people last month.
By CNN’s Steve Almasy. Elise Labott also contributed to this report.