Damascus (AFP) - Syria's President Bashar al-Assad said a suspected chemical weapons attack was a "fabrication" to justify a US strike on his forces, in an exclusive interview with AFP in Damascus.

The embattled leader, whose country has been ravaged by six years of war, said his firepower had not been affected by the attack ordered by US President Donald Trump, but acknowledged further strikes were possible.

Assad insisted his forces had turned over all their chemical weapons stocks years ago and would never use the banned arms.

The interview on Wednesday was his first since a suspected chemical weapons attack that killed dozens of civilians in the rebel-held town of Khan Sheikhun.

"Definitely, 100 percent for us, it's fabrication," he said of the incident.

"Our impression is that the West, mainly the United States, is hand-in-glove with the terrorists. They fabricated the whole story in order to have a pretext for the attack," added Assad, who has been in power for 17 years.

At least 87 people, including 31 children, were killed in the alleged attack, according to the Britain-based Syrian Observatory for Human Rights monitor.