A series of coordinated blasts hit bus stations, an electricity plant and a hospital across two Syrian cities Monday, killing at least 80 people in the first major security breach of President Bashar Assad’s coastal strongholds in the country’s five-year war.

The Islamic State group claimed responsibility for the attack on social media. The militants are not known to maintain a presence in the surrounding countryside, an area in which mainstream rebels and al-Qaida affiliated insurgents form the predominant opposition to Assad’s forces.

The seven closely-coordinated morning blasts in the pro-government cities of Tartus and Jableh targeted civilians in large numbers, and seemed intended to send a message that no part of Syria is safe from violence.

They also underlined the worrying inability of world powers to jumpstart Syrian peace talks in Geneva as the violence worsens.