The European Union on Monday imposed sanctions on 16 Syrian scientists and military officials.

They were sanctioned for their involvement in a chemical attack in northern Syria in April which killed scores of civilians, the union said.

Western intelligence agencies accuse the government of Bashar al-Assad of carrying out the attack, arguing that rebels in the area would not have had the capabilities.

The international chemical weapons watchdog said in June the nerve agent sarin was used.

Syrian officials have repeatedly denied using banned toxins.

Reuters reports that the measures, agreed upon by EU foreign ministers at a meeting in Brussels, target 8 Syrian scientists and 8 top military officials.

Britain’s Foreign Secretary, Boris Johnson, said they showed Europe’s resolve “in dealing with those who are responsible for chemical weapons attacks.’’

This takes the number of people placed under EU sanctions related to the Syrian conflict to 255, the Council of EU governments said in a statement.

Existing EU sanctions are also in place on 67 companies linked to Assad’s government.