The minister told reporters during an official visit in Mauritania on Friday that US Secretary of State Rex Tillerson had informed him of the impending strike on Thursday night.
The US fired 59 Tomahawk cruise missiles from two naval destroyers, the USS Porter and the USS Ross, based in the eastern Mediterranean, at 3.40am Syrian time on Friday. The strike targeted Shayrat Airfield, a military base south of Homs.
At least six Syrian soldiers were killed, according to the UK-based monitoring group Syrian Observatory for Human Rights, which added that “the airbase was almost completely destroyed”.
The strike came just days after a suspected sarin gas attack in the rebel-held town of Khan Sheikhun killed nearly 80 people, including dozens of children, and wounded hundreds more. US President Donald Trump has accused Assad of carrying out the “barbaric attack”.
“The use of chemical weapons is a sad reality,” said Ayrault. “We know this, in spite of the denial, the lies and the propaganda of Bashar al-Assad’s regime.”
“It’s unacceptable, it’s even unbearable, and it must be punished as a war crime,” the minister said of the suspected chemical attack. “The international justice community must give a verdict on Assad and his crimes.”
However, he added that France “is not at war with Syria.”
“We are only fighting the Islamic State armed group (IS) and we have no intention of participating in this war in Syria.”
Ayrault stressed that “it is now more important than ever” to restart peace talks. “We must begin negotiating for a political transition, for reconstruction of the country, and for the return of refugees, and it won’t be done with Bashar al-Assad.”
The US missile strike has escalated American involvement in Syria’s ongoing civil war, marking a point of departure from Obama-era foreign policy regarding military intervention in the country.
“It crossed a lot of lines for me,” said Trump of the Khan Sheikhun incident.
The president’s statement was a thinly veiled reference to former US president Barack Obama, who ultimately decided against enforcing what he called the “red line” on the use of chemical weapons in Syria in 2013.
Trump announced the strike, his biggest military decision since assuming the presidency, in a televised address on Friday just hours after the UN Security Council failed to agree on a probe into the suspected gas attack.
“Tonight I call on all civilised nations to join us in seeking to end this slaughter and bloodshed in Syria, and also to end terrorism of all kinds and types,” he said.
The US president described the strike as being of “vital national security interest”.
Syria has denied the use of chemical weapons and called the US strike “an act of aggression”.
Its Russian ally has also denounced the military action. Kremlin spokesman Dmitry Peskov described it as an “aggression against a sovereign state” that could potentially do “considerable damage” to US-Russia relations.
Backers of the US-led coalition in Syria have declared their support, such as Israeli Prime Minister Benjamin Netanyahu, who said that Trump “sent a strong and clear message that the use and spread of chemical weapons will not be tolerated.”
German Foreign Minister Sigmar Gabriel said the strike was “understandable” following the suspected sarin gas attack, while Shinzo Abe, Japan’s Prime Minister, said his country “supports the US government’s resolve”.