Turkey has erected 290 kilometers (180 miles) of a planned 511-kilometer (317 miles) "security wall" along its border with war-torn Syria, local media reported on Sunday, quoting the head of the body building the structure.

The wall is made from portable concrete blocks each weighing seven tons. The blocks are 2-meters thick (6.5-foot) at the base and 3-meters (10-foot) high, topped by a meter of razor wire. Along the entire wall roads are being built for military patrols and watch towers are being erected.

Ergun Turan, the head of the massive state housing developer TOKI that is tasked with building the wall in coordination with the defense and finance ministries, said the wall stretches along border sections in Hatay, Kilis, Sanliurfa, Mardin, Sirnak and Gaziantep provinces.

He said the portable nature of the blocks would allow Turkey to move them in the future when the security situation improves.

Turkey shares a 911-kilometer (566 miles) border with Syria. Ankara is concerned about the Syrian Kurdish YPG militia and has been under pressure from the United States and Europe to seal its porous southern border, which has been used by the so-called "Islamic State" (IS) and other rebel groups for smuggling weapons, supplies and fighters. After a military intervention into northern Syria in August, the Turkish military and allied rebel groups cleared IS from a section of the border.

However, human rights groups have voiced concern the wall will trap Syrian civilians fleeing conflict on the other side of the border at a time Turkey tightens its refugee policy. Rights groups have documented security forces firing on fleeing civilians and carrying out illegal pushbacks.

"The wall is a further indication that the Turkish government is determined to stop people, including refugees, coming through," said Andrew Gardner, Amnesty International's Turkey researcher. He added that the Turkish government should overhaul its border policy and ensure regular routes are open for those fleeing violence.

"This will ensure that people in need of safety can access it and also enhance border security and deal a blow to smugglers," he said.

Seeking to stem migration to Europe, the EU has remained largely silent about the wall's impact on people seeking asylum. 

Turkey has taken in more than three million Syrian refugees.