The warning came from US Ambassador Nikki Haley during an emergency meeting of the UN Security Council called by France and Britain following the attack in the early hours Tuesday on a rebel-held town in Idlib province.

“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,” Haley said, without elaborating.

Britain, France and the United States, which holds the council presidency in April, have presented a draft resolution demanding a full investigation of the attack.

But Russia said the text was “categorically unacceptable.”

Negotiations continued on the proposed measure throughout most of the day. Diplomats said it could come up for a vote at the council as early as Thursday.

“We very much hope that it will be possible for everyone to come together,” British Ambassador Matthew Rycroft said. “If not, we will press ahead.”

Failure to agree on a compromise text could prompt Russia to use its veto to block the draft resolution.  Moscow has used its veto seven times to shield Syria from UN action. 

Haley lashed out at Russia for failing to rein in Syria, standing in the council chamber to hold up photographs of victims — one showing a child lying lifeless, a mask covering his face. 

“How many more children have to die before Russia cares?” she asked.

“If Russia has the influence in Syria that it claims to have, we need to see them use it,” she said. “We need to see them put an end to these horrific acts.”

At least 72 people, among them 20 children, were killed in the strike on the town of Khan Sheikhun, and dozens more were left gasping for air, convulsing, and foaming at the mouth, doctors said.

It is thought to be the worst chemical weapons attack in Syria since 2013, when sarin gas was used.

– France urges US engagement -Britain, France and the United States blame President Bashar al-Assad’s forces for the attack, but the Syrian army has denied any involvement.

“If we are not prepared to act, then this council will keep meeting, month after month to express outrage at the continuing use of chemical weapons and it will not end,” Haley said.

“We will see more conflict in Syria. We will see more pictures that we can never unsee.”

French Ambassador Francois Delattre called on Russia to ratchet up pressure on Assad but also had a message for the US administration.

“Frankly we also need an America that is seriously committed to a solution in Syria and puts all its weight behind it. If not now, when?” Delattre told reporters.

The draft resolution backs a probe by the Organisation for the Prohibition of Chemical Weapons and demands that Syria cooperate to provide information on its military operations on the day of the assault.

Russia’s Deputy Ambassador Vladimir Safronkov told the council that the proposed resolution was hastily prepared and unnecessary, but voiced support for an OPCW inquiry.

“The main task now is to have an objective inquiry into what happened,” he said. 

Russia turned up at negotiations with a rival draft resolution that made no reference to specific demands that Damascus cooperate with an inquiry, diplomats said.

The Western-backed text calls on Syria to provide flight plans, flight logs and other information on its military operations on the day of the assault and to hand over the names of commanders of helicopter squadrons.

Delattre told reporters that negotiations were being held “in a good spirit” and that “there is a chance” for agreement. 

But other diplomats sounded more pessimistic, saying a Russian veto appeared likely. “It’s not going well,” a council diplomat said. DM