US-led strikes 'failed to deter' Assad from chemical warfare: Israel

US-led missile strikes against the Syrian regime have failed to destroy its chemical stockpiles and have not deterred their use in future, Israeli officials have reportedly said.

Israeli intelligence officials told local daily Yedioth Ahronoth on Tuesday that the attack on regime military installations last weekend was unsuccessful in achieving its objectives.

"If President Trump had ordered the strike only to show that the US responded to Assad's use of chemical weapons, then that goal has been achieved," one official said.

"But if there was another objective - such as paralysing the ability to launch chemical weapons or deterring Assad from using it again - it's doubtful any of these objectives have been met."

The United States, France and Britain conducted the strikes in response to a suspected gas attack on Douma, near Damascus, that reportedly left more than 40 people dead.

Western powers have blamed the chemical attack on the regime of Syrian President Bashar al-Assad. The Syrian government denies involvement.

"Only a partial damage was caused to the chemical weapons stockpiles and launch capabilities," Israeli officials said.

"[The assertion] that Assad's ability to use chemical weapons has been fatally hit has no basis," they added.

Chemical weapons attacks have killed thousands of people since the start of Syria's conflict, with the UN blaming four attacks on the Syrian regime and a fifth on the Islamic State group.

In 2013, up to 1,400 people were killed in two chemical weapons attacks on the opposition-controlled Damascus suburbs of Eastern and Western Ghouta.

The international outcry that followed Ghouta resulted in a Russian-brokered deal for Syria to relinquish its chemical weapons stockpile in September 2013.

The deal was struck to avoid US military action against Syria.

Since Ghouta and the subsequent deal, civilians in Syria have continued to be bombed with chemical cylinders containing chlorine and other harmful substances.

In 2017 a sarin gas attack on the rebel-held town of Khan Sheikhun killed more than 80 people, prompting Washington to bomb a regime air base.