A suicide bomber let off an explosive device outside the Turkish parliament just hours before it was set to reopen after summer recess, officials said.
Turkey’s interior minister also tweeted that two police officers were injured during the attack.
It happened just before president Recep Tayyip Erdogan was set to deliver an address to parliament.
Television footage showed bomb squads working near a parked vehicle in the area which is located near Turkey’s National Assembly.
There was no immediate information on the attackers. However, Kurdish and far-left militant groups as well as the Islamic State group have carried out deadly attacks in the past.
Last year, six people were killed and 81 were wounded in an explosion in Istanbul. Turkey blamed Kurdish militants for the attack.
In 2015 and 2016, Kurdish militants, Islamic State and other groups either claimed or were blamed for several attacks in major Turkish cities.
Justice minister Yilmaz Tunc said an investigation had now been launched into the “terror attack”. “These attacks will in no way hinder Turkey’s fight against terrorism. Our fight against terrorism will continue with more determination,” he said.
Police cordoned off access to the city centre and increased security measures, warning citizens that they would be conducting controlled explosions of suspicious packages.
At 7.30pm, President Tayyip Erdogan was set to attend the opening of parliament, which in the coming weeks is expected to consider ratifying Sweden’s bid to join Nato after Turkey had raised initial objections.
Turkish media reported that authorities were carrying out checks of the parliament after the blast at the ministry. A source told Reuters that the entrance was open but no cars were allowed through as part of the precautions.