IRAQ has declared an end to its three-year war against Islamic State.

Prime Minister Haider al-Abadi formally announced the victory in an address to the nation aired on Iraqi state television on Saturday evening.

He said: "Honourable Iraqis, your land has been completely liberated. The liberation dream has become a reality. We achieved victory in difficult circumstances and with God's help, the steadfastness of our people and the bravery of our heroic forces we prevailed."

"The flag of Iraq is flying high today over all Iraqi territory and at the farthest point on the border," he added.

Iraqi forces mopped up the last pockets of IS fighters from Iraq's western deserts on Saturday, securing the country's border with Syria.

The step marked the end of combat operations against the extremists, also known as Daesh.

Following al-Abadi's remarks, his office declared a public holiday today in celebration of the victory.

Prime Minister Theresa May hailed the "historic moment", though cautioned that while the extremist group no longer held significant territory in Iraq or Syria, it had not yet been fully defeated.

May said: "I congratulate prime minister Abadi and all Iraqis on this historic moment. I pay tribute to the Iraqi security forces for their courage and sacrifice.

"Daesh no longer hold significant territory in Iraq or Syria. This signals a new chapter towards a more peaceful, prosperous country."