4 Dead in Terrorist Attack at Turkish Aviation Company

Four people were killed and 14 wounded in what the government called a terrorist attack at the Turkish Aerospace Industries' headquarters on Wednesday, after witnesses said they had heard gunfire and an explosion at the site near Ankara.

Interior Minister Ali Yerlikaya said two attackers were killed in the attack, adding three of the injured are in critical condition. TV broadcasters showed footage of armed assailants entering the TUSAS building.

"Two terrorists were neutralized in the terror attack on the TUSAS Ankara Kahramankazan site. Sadly, we have 3 martyrs and 14 wounded in the attack," Yerlikaya said.

Turkish President Tayyip Erdogan, alongside Russia's Vladimir Putin at a BRICS conference in the Russian city of Kazan, condemned the attack and accepted Putin's condolences. NATO, the United States and the European Union also condemned the attack.

The cause of the blast and perpetrators of the attack remained unclear. No group had claimed responsibility. Prosecutors have launched an investigation, state-run Anadolu Agency reported.

Some media reports claimed a suicide attack had occurred and that there were hostages inside the building, though officials have not confirmed this.

Witnesses told Reuters that employees inside the building were taken by authorities to shelters and no one was permitted to leave for a few hours. They said the blasts they heard may have taken place at different exits as employees were leaving work for the day.

Witnesses later said evacuation of personnel from the TUSAS campus had started and the buses were allowed to leave as the operation had ended.

Broadcasters showed images of a damaged gate and footage of an exchange of gunfire in a parking lot, as well as attackers carrying assault rifles and backpacks as they entered the building. Ambulances and helicopters later arrived.

TUSAS is Turkey's largest aerospace manufacturer, currently producing a training craft, combat and civilian helicopters, as well as developing the country's first indigenous fighter jet, KAAN. Owned by the Turkish Armed Forces Foundation and government, it employs more than 10,000 people.

NATO Secretary General Mark Rutte condemned the attack and said the military alliance would stand with its ally Turkey. (Reporting by Mert Ozkan, Ece Toksabay and Tuvan Gumrukcu; Editing by Jonathan Spicer, Alison Williams, Alexandra Hudson)