As Syrian leader Bashar al-Asad\'s regime fights to stay in power, one man has emerged as the symbol of the dynasty\'s brutal military might -- the president\'s feared younger brother Maher. Lieutenant Colonel Maher al-Asad heads the Syrian army\'s elite Fourth Division, which oversees security in the capital, along with the Republican Guard, and is a central figure in the tight-knit Assad clan. His reputation as an impassive military leader has been consolidated in recent months as the Asad regime tightens its grip on a popular revolt against nearly five decades of rule by the Baath Party. Observers say Maher\'s influence is steadily on the rise as he spearheads a fierce crackdown on protesters across the country that has left more than 1,200 people dead, according to rights groups. \"Judging by reports from the field, Maher al-Asad is everywhere at once, directing repression singlehandedly,\" said one Damascus-based analyst, who did not wish to be named because of the sensitivity of the subject. \"This reflects, I think, a perception that the ruling family is fighting for its life, and willing to crush society if that is what it takes,\" he told AFP. \"Maher is the most obvious symbol of that struggle.\" The behind-the-scenes 43-year-old was among 13 members of Asad\'s inner circle who were slapped last month with punitive sanctions by the European Union, United States and Canada, as the international community sought to pressure the regime to stop the repression. Turkish Prime Minister Recep Tayyip Erdogan singled out Maher al-Asad for criticism last week, accusing him of inhumane behaviour. \"I say this clearly and openly: from a humanitarian point of view, (Bashar\'s) brother is not behaving in a humane manner,\" he said. Bashar\'s father, the late Syrian leader Hafez al-Asad, had also shared power with his brother, charging Rifaat al-Asad with heading the Saraya al-Difaa (\"Defence Companies\"), an armed battalion independent of the army. Upon orders by Hafez al-Asad, Rifaat\'s troops carried out the 1982 Hama massacre, bombing the town in central Syria indiscriminately to put down an uprising by the Sunni Muslim Brotherhood. While there are no official figures, between 10,000 and 40,000 people are estimated to have been killed. Rifaat was later exiled and now lives in London. Since the uprising in Syria erupted mid-March, Maher al-Asad has remained in the shadows but quickly gained a reputation as a ruthless commander while the army laid siege to rebellious town after rebellious town. \"Bashar al-Asad is the leader, the face, and Maher is the enforcer who wears the frown,\" said Joshua Landis, a Syria expert and professor at the University of Oklahoma. \"Today, he is extremely influential, as the regime is hanging on a military thread. \"Maher holds the key.\" But there is little evidence as to whether his reputation is true to reality or propagated by the regime to help preserve the softer image of Bashar al-Asad as a reformer. \"The secret that Hafez al-Assad discovered was that personal loyalty was at the heart of stability -- family, village, sect,\" Landis told AFP. \"The Syrian regime is in many ways a family affair and there is accordingly a division of labour.\" Thousands of Syrian refugees have fled into neighbouring Lebanon and Turkey, where they recount what they say are killings at the hands of Maher al-Assad\'s men. But as reports spread of that his black-clad troops are surfacing in villages at Syria\'s northern and southern borders, and the press is squeezed out of the country, experts say there is no concrete evidence that Maher is -- or can be -- everywhere. \"The praetorian guard Maher al-Asad commands is tasked with protecting the regime in and around the capital,\" said the Damascus-based analyst. \"It sounds unlikely that it would have been sent across the country when Damascus itself is simmering and the palace needs it close at hand.\"