“Today’s news is awful,” Mogherini said in an interview with media organisations in Brussels on the sidelines of a EU-UN conference that was meant to focus on the post-conflict situation in Syria.
“But this is a dramatic reminder of the fact that the situation on the ground still continues to be dramatic in many different parts of Syria,” Mogherini said.
“And obviously, there is a primary responsibility there from the regime and first and foremost because it has the primary responsibility of protecting its people and not attacking its people. The issue of accountability is key for the EU but also for the conference itself.”
Britain meanwhile condemned the attack in the northwestern town of Idlib and called for those responsible to be held to account.
“Horrific reports of chemical weapons attack in Idlib, Syria. Incident must be investigated and perpetrators held to account,” Foreign Secretary Boris Johnson said on Twitter.
A Syrian security source on Tuesday said the gas attack report was a “false accusation”.