One person was killed and three injured in clashes between Syrian forces and opposition rebels in northern Idlib city on Wednesday. On the outskirts of Idlib, a massive explosion rocked an army checkpoint in the area of Al-Hassem, the opposition Syrian Observatory for Human Rights. The London-based organization gave no further details. Activists in the central city of Homs said shells fell on the area of Al-Rastan, the scene of heavy fighting Tuesday between rebels and the army, according to a report of DPA.