The US government imposed "sweeping sanctions" on Syrian officials in response to what the US says was a sarin gas attack on civilians earlier this month, the Treasury Department announced on Monday.
The Treasury ordered a freeze on all assets in the United States belonging to 271 employees of the Syrian Scientific Studies and Research Center (SSRC), and blocked any American person or business from dealing with them.
The SSRC was responsible for producing the chemical weapons Washington believes were used in the attack and the means to deliver them, the statement said.
A suspected chemical attack left 87 dead, including many children, in rebel-held territory in Idlib province on April 4, with the West accusing Syrian President Bashar al-Assad of being responsible.
"These sweeping sanctions target the scientific support center for Syrian dictator Bashar al-Assad's horrific chemical weapons attack on innocent civilian men, women, and children," Treasury Secretary Steven T. Mnuchin said in a statement.
"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."
Treasury already had imposed sanctions against 18 Syrian officials in January, and Mnuchin said the administration "will relentlessly pursue and shut down the financial networks of all individuals involved with the production of chemical weapons used to commit these atrocities."
The United States also fired 59 cruise missiles at a Syrian airfield on April 7 in response to the suspected chemical weapons attack.