Islamic State militants on Thursday seized control of a civilian airport in the coastal Libyan city of Sirte after violent clashes with Fajr Libya, a pro-Islamist political military group that controls Tripoli.

The Islamic State affiliate in Libya confirmed the airport seizure reports and said it also took control of a number of buildings linked to "Big artificial river" project - the biggest waterworks in the world, ANSA reported. It was first time the Islamic State in Libya has recorded such a strategic and military success.

Mohammed al-Shamia, a spokesman for the Tripoli-based unrecognized government, said the Islamic State militants took over al-Qardabiya air base after they forced the government-linked Battalion 166 militia to retreat, the Associated Press reported. The spokesman further said the government forces had pulled out of the airport to redeploy as part of an operation to secure two areas east and west of Sirte, according to Agence France-Presse (AFP).  "After they left, Islamic State group fighters entered the base which had been completely emptied of equipment, except for one military plane which is out of use," he said, AFP reported.

Sirte, the hometown of late dictator Muammar Gaddafi, who was deposed in 2011, is located 450 kilometers east of Tripoli. The coastal city has been a bastion of extremism and sporadic fighting among rival factions.

In another development, the Tripoli-based government run by the Fajr Libya group has warned Europe over Mediterranean migrant boats crises. ''If the EU will enter Libyan waters to stop migrant boats without our permission, we will defend ourselves," Khalifa al-Ghweil, head of Tripoli-based government, said in an interview, according to the ANSA.

Libya, an oil-rich country, is divided between two rival governments. In August of last year, Islamic militias forced an elected government to move from Tripoli to Tobruk, a far eastern city near the Egyptian border, according to DPA news agency. Extremist militants, in recent months, captured and beheaded dozens of Christian laborers and Egyptians and Ethiopians migrants.