The US has sanctioned 271 employees of a Syrian government agency it blames for developing chemical weapons.

The move comes after at least 80 people, including dozens of children, were killed in the 4 April attack in Khan Sheikhoun, a rebel-held town in northern Syria.

The US believes sarin gas was dropped by Syrian aircraft and Turkey says post-mortems performed on victims of the attack show chemical weapons were used.

The Syrian government, however, has denied this.

Syria: 'Either sarin or a sarin-like substance'

Syria's Scientific Studies and Research Center (SSRC) is described by Bashar al Assad's government as a civilian research centre, but US Treasury officials said on Monday that it is focused "substantively on the development of biological and chemical weapons".


The sanctions mean US banks must freeze the employees' assets and American companies are banned from doing business with them.

Treasury officials said that those on the sanctions list were "highly educated" and were likely to be able to travel out of Syria and use the international financial system, even if they don't have assets outside their own country.

US Treasury Secretary Steven Mnuchin said: "These sweeping sanctions target the scientific support centre for Syrian dictator Bashar al Assad's horrific chemical weapons attack on innocent civilian men, women, and children.

Gas attack dad wants Trump to act in Syria

"The United States is sending a strong message with this action that we will hold the entire Assad regime accountable for these blatant human rights violations in order to deter the spread of these types of barbaric chemical weapons.

"We take Syria's disregard for innocent human life very seriously, and will relentlessly pursue and shut down the financial networks of all individuals involved with the production of chemical weapons used to commit these atrocities."

Mr Mnuchin said it was one of the largest such sanctions in US history.

UK Foreign Secretary Boris Johnson welcomed the sanctions, saying they "send a clear signal that actions have consequences and seek to deter others from similar acts of barbarism.

"We welcome the role sanctions play in increasing pressure on the Syrian regime to turn away from its military campaign.

"We will continue our efforts to hold accountable those responsible for chemical attacks, including through the UN and EU, and to energise international support for the UN-led political process.

"Only a political settlement will bring an end to the war in Syria."

The SSRC has been hit with sanctions before - it was blacklisted by George W Bush's administration in 2005 after being accused of creating weapons of mass destruction.

Under Barack Obama's presidency in July 2016, people and companies were sanctioned for supporting the centre and in January this year another six of its officials were also sanctioned.