A huge explosion outside the headquarters of Turkish Aerospace Industries (TAI) near Ankara left a number of people "dead and injured", Turkey’s interior minister said Wednesday, describing it as a "terrorist attack".

"A terrorist attack was carried out against the Turkish Aerospace Industries... Unfortunately, we have martyrs and injured people," Ali Yerlikaya wrote on X, using a term often used for the deaths of soldiers or police.

Footage from 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 some 40 kilometres (25 miles) north of Ankara.

Haberturk TV said there was an ongoing "hostage situation" without giving further details, while the private NTV television spoke of gunshots after the blast which took place around 4:00 pm (1300 GMT).

There was no immediate claim for the attack.

The blast occurred as a major trade fair for the defence and aerospace industries was taking place in Istanbul which was visited this week by Ukraine’s top diplomat.

Turkey’s defence sector, which is widely known for its Bayraktar drones, accounts for nearly 80 percent of the nation’s export revenues with revenues expected to top 10.2 billion dollars in 2023.