TRIPOLI, May 23 (Xinhua) -- UN Support Mission in Libya (UNSMIL) on Wednesday condemned the Islamic State (IS) suicide attack on a military checkpoint in eastern Libya.

"UNSMIL condemns the IS-claimed attacks that took place yesterday in Libya's east near Ajdabiya, resulting in casualties among the Libyan National Army," the mission said in a statement.

"The upsurge of IS-claimed attacks is a serious threat that should not go unnoticed by the Libyan and the international community," the statement added.

IS has claimed responsibility for a suicide car bomb Tuesday targeting a checkpoint of the eastern-based army near Ajdabiya, some 160 km south of Benghazi, Libya's second largest city.

Two soldiers were killed in the attack and two others were injured.

IS attacks in Libya have increased significantly since the beginning of the year, targeting security checkpoints and government buildings.

Two IS suicide bombers attacked the Libyan National Commission of Elections in the capital Tripoli earlier in May, killing 14 people and injuring 10 others.

Following the 2011 uprising that toppled former leader Gaddafi's regime, Libya has been plagued by insecurity and escalating violence.