PALM BEACH, United States (AFP) — US President Donald Trump ordered a massive military strike against Syria on Thursday in retaliation for a chemical attack with a sarin-like nerve agent which Washington blames on President Bashar al-Assad.

A White House official said 59 precision-guided missiles hit Shayrat Airfield in Syria, where the United States believes Tuesday’s deadly attack was launched. The official had earlier given the number of missiles involved as 70.

The missiles were blasted from the USS Porter and the USS Ross, which belong to the US Navy’s Sixth Fleet and are located in the eastern Mediterranean. A US official said the missiles targeted aircraft and runways at the base.

“This site was associated with the Syrian regime’s chemical weapons program and directly linked to the horrific chemical weapons attack April 4th,” the White House official said.

“We assess with a high degree of confidence that the chemical weapons attack earlier this week was launched from this site by air assets under the command of the Assad regime,” the official added.

“We also assess, with a similar degree of confidence, that the Assad regime used a chemical nerve agent consistent with sarin in these attacks.”

Inhaled or absorbed through the skin, sarin gas kills by crippling the respiratory center of the central nervous system and paralyzes the muscles around the lungs.

Sarin was used by Iraqi dictator Saddam Hussein’s regime to gas thousands of Kurds in the northern town of Halabja in 1988.

The UN Security Council failed Thursday to reach agreement on demands for a thorough investigation of the strike in northwestern Syria’s Khan Sheikhun, in which at least 86 people, including 27 children, died.