BAGHDAD, Feb. 20 (Xinhua) -- Iraqi security said Wednesday that 24 Islamic State (IS) militants, who infiltrated from neighboring Syria, were captured in Iraq's northern province of Nineveh.

The Iraqi Army's Chief of Staff Othman al-Ghanimi told reporters at a press conference near the provincial capital Mosul that four of the captured were group leaders.

Al-Ghanimi's comment came during his visit to Nineveh's Operations Command which is responsible for the security situation in northern Iraq, including the border areas with Syria.

He stressed the need to take precautionary security measures to maintain security in the city of Mosul and other areas in the province.

On Tuesday, Iraqi Prime Minister Adel Abdul Mahdi said that Iraq is concerned about developments of the battles in neighboring Syria, which is witnessing the clearing of the last pocket of IS extremist group near the Syrian border with Iraq.

Iraqi security force and paramilitary Hashd Shaabi brigades are deployed on the borderline between Syria and Iraq, which extends to some 600 km in west of the two provinces of Nineveh and Anbar.

The long borderline between the two countries has long been used by insurgent groups and IS militants for logistic support and to carry out cross-border attacks in Iraq since the U.S.-led invasion in 2003.