Heavy fighting broke out on Friday between army forces and foreign-backed militants on the outskirts of the town, which is located in the Eastern Ghouta area, the so-called the Syrian Observatory for Human Rights (SOHR) said.
Syrian army tanks pounded militant positions in Mleiha, while Syrian warplanes carried out four air raids in the town.
The attack came a day after army bombing killed 22 militants in Mleiha, which is held by militants.
The town is strategically significant as it is located near the army-held city of Jaramana, which comes under frequent fire by militant forces.
Meanwhile, fighting has resumed in Latakia in western Syria, where two weeks of heavy clashes have left 300 army forces and militants dead.
Syria has been plagued by relentless militancy since March 2011. Damascus says the West and its regional allies have been fuelling violence in Syria by providing militants with money and weapons.
On Tuesday, the so-called SOHR, which relies on a network of spies working for the foreign-backed opposition, said that the total deaths resulting from the ongoing crisis in Syria amounted to 150,344 people.
The London-based pro-opposition group said there were 51,212 civilians, among the dead, including 7,985 children.
SHI/SHI