Ankara/IBNS: Two terrorists and 4 civilians were killed while several others were injured in a huge explosion outside the headquarters of Turkish Aerospace Industries (TAI) near Ankara, Turkey's interior minister said Wednesday, describing it as a "terrorist attack", media reports said.

"A terrorist attack was carried out against the Turkish Aerospace Industries... Unfortunately, we have martyrs and injured people," Ali Yerlikaya wrote on X.

Local media footage showed clouds of smoke and a large fire raging at the site in Kahramankazan, a small town some 40 kilometers north of Ankara.

According to Haberturk TV, there was an ongoing "hostage situation" while the private NTV television spoke of gunshots after the blast. Video footage circulating in social media also showed two terrorists opening fire.

Images shown by Haberturk suggested one attacker was a woman, while Sabah newspaper published a CCTV image from cameras at the building's entrance of a black-clad young man with a moustache carrying a rucksack and what appeared to be an assault rifle.

No terrorist outfit has so far claimed responsibility for the attack.

Turkish Transport Minister Abdulkadir Uraloglu and opposition leader Ozgur Ozel condemned the attack.

"I condemn the terrorist attack against TAI facilities in Kahramankazan... I condemn terrorism, no matter who or where it comes from," Ozel wrote on X.