Turkey’s Interior Minister says a number of people have been killed and injured after an attack on the buildings of Turkish aerospace and defense company TUSAS.

Ali Yerlikaya did not provide further details about the attack on Turkey’s aerospace industry, located on the outskirts of the capital Ankara.

“A terrorist attack was carried out on the facilities of the Turkish aerospace industry Ankara Kahramankazan,” he wrote in a post on social media.

Images of the scene broadcast by local media initially showed huge clouds of smoke and a large fire raging at the site in Kahramankazan, a small town about 40 kilometers (25 miles) north of Ankara. Media have reported a loud explosion at the site and shown images of gunfire there.

There was no immediate claim for the attack.

Emergency services were sent to the site, state-owned Anadolu Agency said.

TUSAS is one of Turkey’s most important defense and aerospace companies. It produces, among other things, KAAN, the country’s first national fighter aircraft.

The blast occurred as a major trade fair for the defense and space industries took place in Istanbul, which was attended this week by Ukraine’s top diplomat.

Turkey’s defense sector, widely known for its Bayraktar drones, accounts for almost 80 percent of the country’s export revenues, with sales expected to exceed $10.2 billion by 2023.