US Secretary of State Rex Tillerson has said that Russia needs "to think carefully" about its support for Syrian dictator Bashar al-Assad after the devastating chemical weapons attack that took place in Idlib.

The Syrian regime is accused of using sarin gas in the rebel-held area, leaving 73 people dead – including 23 children – and many struggling with breathing problems.

Before a meeting with Mexican Foreign Secretary Luis Videgaray Caso on Wednesday (5 April), Tillerson was asked by a reporter whether the crisis in Syria could be resolved without Russian cooperation.

The US has strongly condemned the attack and blamed Assad, and Tillerson is heading to Russia in a week's time.

"Well, there's no doubt in our mind that the Syrian regime under the leadership of Bashar al-Assad is responsible for this horrific attack," Tillerson replied.

"We think it's time that the Russians really need to think carefully about their continued support of the Assad regime."

President Donald Trump condemned the attack during a joint press conference with King Abdullah of Jordan. "A chemical attack that was so horrific in Syria, against women and small children, and even beautiful little babies, and their deaths, was an affront to humanity," Trump said.

"These heinous acts by the Assad regime cannot be tolerated. The US stands with our allies across the globe to condemn this horrific attack."

The US ambassador to the United Nations, Nikki Haley, sent a strong indication that the US might seek to take action.

While holding up pictures of victims of the attack, Haley said: "When the United Nations consistently fails in its duty to act collectively, there are times in the life of states that we are compelled to take our own action."

Nikki Haley Syria
US Ambassador to the UN Nikki Haley holds photographs of victims during a meeting at the United Nations Security Council on Syria on 5 April 2017 Shannon Stapleton/Reuters