TRIPOLI, May 15 (Xinhua) -- Spokesman of the eastern-based Libyan army, Ahmad Mismari, on Tuesday said the army has captured 21 terrorists in the eastern city of Darna, after the army forces advanced in the south of the city.

"The armed forces carried out a pre-planned combat mission today, where the enemy positions in Duhr al-Hamr, al-Tila, and Matrouba areas were controlled. The enemy suffered heavy losses of individuals and vehicles," Mismari said in a statement.

The spokesman also said the arrested terrorists descent from six foreign nationalities, and confirmed that the army is "proceeding with a steady and orderly pace towards the liberation of Darna from terrorism."

The army is launching a military operation to take over Darna from the extremists who control the coastal city.

Since 2015, Darna has been besieged by Haftar's army, which demands that the Shura Council of the Mujahideen in Darna, a coalition of Islamist militias seeking to implement Sharia law in the city, leave. The army accuses the armed group of being loyal to al-Qaida.

Earlier in April, Haftar announced that his forces would take over Darna "as demanded by the people."