At least three people were killed in an explosion in the northern Syrian city of Afrin on Sunday, according to a British-based monitor of the Syrian war. Nine other people, including fighters, were wounded in the blast, the<span style="background-color:rgba(255, 255, 0, 0.3)"> </span>Syrian Observatory for Human Rights said. Turkey's state-run Anadolu agency said the attack was a twin bombing. One explosive targeted a bus, while the second was placed in a rubbish container. Pictures posted on social media networks showed a wrecked green bus. Gory videos purported to show corpses on the floor. _______________________ <strong>Read more from Opinion</strong> <strong><a href="https://www.thenational.ae/opinion/comment/india-s-plan-for-the-world-s-largest-public-healthcare-system-is-a-big-idea-but-is-it-doomed-to-failure-1.702136">Syria's Afrin region hit by spate of kidnappings </a></strong> <strong><a href="https://www.thenational.ae/opinion/comment/safer-internet-day-we-must-work-together-to-make-the-digital-world-safer-for-children-1.701726">Afrin beginning to look less like a victory for Turkey as YPG mounts guerrilla campaign</a></strong> <strong><a href="https://www.thenational.ae/opinion/comment/put-down-your-smartphone-and-stop-watching-great-art-through-a-viewfinder-1.701927">Miscalculations in Afrin have dramatically changed the facts on the ground</a></strong> _________________________ It was not immediately clear who was behind the attack. Anadolu said it believes the Kurdish People's Protection Units (YPG) are responsible. The town in north-western Syria was once a bastion for the Syrian Kurds who have fought on the ground for the US-led coalition against ISIS. But Turkish troops and their Syrian rebel allies seized the enclave from the Kurds last year in a two-month air and ground offensive. The attack on Sunday comes on the first anniversary of the Turkish offensive on the Kurdish-majority region. Turkey launched Operation Olive Branch on Afrin to drive out the Syrian Kurdish YPG, which it sees as an extension of the outlawed Kurdistan Workers Party (PKK) that has waged an insurgency since 1984 on Turkish soil.