(Al Jazeera) – Forces loyal to Syrian President Bashar al-Assad are intensifying their offensive over key rebel-held towns in the southern province of Deraa, as thousands of people continue to flee the area, witnesses tell Al Jazeera. Clashes broke out on Tuesday between pro-government forces, which have amassed on the outskirts of the town of Basr al-Harir, as fighting between the two sides escalated. “At least 200 air strikes and 150 barrel bombs targeted Basr al-Harir this morning as government forces moved in on the village,” said Jihad Hamza, a pro-opposition activist in Deraa.