Iraq is building a new security fence along its long desert border with Syria, the latest attempt to stop Isis fighters entering the country.

Construction of the first 20 km (12.4 miles) of barbed wire fence and six-metre-wide trench began last week, Anbar governorate spokesperson Anwar Hamid Nayef said.

The barrier will also use surveillance towers, thermal cameras and drones to spot potential militants trying to cross into the country.

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If the initial section near the border town of al Qaim is evaluated as effective by Baghdad and US security officials, the fence will be extended across the entire 370 mile border, Mr Nayef added.

Isis controlled around one third of Iraq at the height of its power in 2014 after it managed to cross over from Syria to ambush the Iraqi army in the northern city of Mosul, declaring the creation of a so-called caliphate across the two countries. It controlled several major cities and reached as far as the outskirts of Baghdad.

Iraqi Christians celebrate liberation from Isis Show all 10 1 /10 Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis An Iraqi Christian prepares for the first Sunday Mass at the Church of the Immaculate Conception in Qaraqosh Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi priests hold the first Sunday mass Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi Christian soldiers attend the first Sunday mass at the Grand Immaculate Church since it was recaptured from Islamic State in Qaraqosh Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis An Iraqi Christian soldier holds his weapon during the first Sunday mass Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis An Iraqi Christian soldier lights a candle Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi priests hold the first Sunday mass at the Grand Immaculate Church since it was recaptured from Islamic State Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi priests hold the first Sunday mass Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi Christian soldiers attend the first Sunday mass at the Grand Immaculate Church since it was recaptured from Islamic State in Qaraqosh, near Mosul in Iraq October 30, 2016. REUTERS/Ahmed Jadallah - RTX2R245 Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis An Iraqi Christian soldier attends the first Sunday mass at the Grand Immaculate Church since it was recaptured from Islamic State in Qaraqosh, near Mosul in Iraq October 30, 2016. REUTERS/Ahmed Jadallah - RTX2R256 Reuters Iraqi Christians celebrate liberation from Isis Iraqi Christians celebrate liberation from Isis Iraqi Christian soldiers attend the first Sunday mass at the Grand Immaculate Church since it was recaptured from Islamic State in Qaraqosh, near Mosul in Iraq October 30, 2016. REUTERS/Ahmed Jadallah - RTX2R269 Reuters

While Iraq officially declared victory over Isis in December last year, the group has morphed into an insurgency based in the desert which stretches between eastern Syria and western Iraq.

Militants maintain sleeper cells inside Iraqi cities and continue to carry out terrorist attacks against the security services as well as civilians: the bodies of eight kidnapped men were found along a highway north of Baghdad last week.

The US-led international coalition against Isis, as well as the Iraqi air force, continues to launch airstrikes on Isis territory and targets inside the country.

Hundreds of men, women and minors remain in jails across Iraq awaiting trial for being members of Isis. At least 117 people were executed by hanging in 2017 - most after evidence gathering and trials which human rights groups said fell far below international standards.