A "terrorist attack" took place near Turkey's parliament in Ankara on Sunday leaving two police officers injured, the interior ministry said.
The powerful explosion, which was followed by large flames, was heard for several kilometres from the site of the attack.
The ministry said two attackers arrived in a commercial vehicle around 9:30 am (0630 GMT) "in front of the entrance gate of the General Directorate of Security of our Ministry of the Interior, and carried out a bomb attack."
"One of the terrorists blew himself up and the other was neutralised," the ministry added on social media, saying two officers received "minor injuries".
The targeted district is home to several other ministries and the Turkish parliament, which was due to reopen today with an address from President Recep Tayyip Erdogan, according to Turkish media.
Media said the president was due to speak to deputies during the day's session.
TV channel NTV reported gunfire in the cordoned-off area after the explosion, where many police vehicles and ambulances were seen.
The Ankara police headquarters said on the social media platform X, formerly known as Twitter, that it was carrying out "controlled explosions" of "suspicious packages" to prevent other explosions.
The Ankara prosecutor's office said it was opening an investigation and banned access to the area.
Local media was asked to stop broadcasting images from the scene of the attack.
Nobody immediately claimed responsibility for the blast.
- Ankara attacks -
Erdogan was set to speak during the opening of this parliamentary session, which must validate Sweden's entry into the NATO alliance.
Hungary and Turkey in July lifted their vetoes against Sweden's entry into the Atlantic alliance, but have been slow to ratify its membership.
Erdogan indicated in July that ratification by the Turkish parliament would not take place before October, but it is expected to be approved during this parliamentary year.
For months, Erdogan has been putting pressure on Sweden to take action against Koran desecrations that have strained relations between the two countries.
Finland became NATO's 31st member country in April, after three decades of military non-alignment and in the midst of the war in Ukraine.
The capital Ankara has been the scene of several attacks, particularly during the years 2015 and 2016 -- many claimed by the outlawed separatist group the Kurdistan Workers' Party (PKK), or the Islamic State group.
The PKK, which has waged an insurgency against the Turkish state since 1984, is blacklisted as a terror group by Ankara and its Western allies.
PKK-affiliated Kurdish militants control most of northeastern Syria.
In October 2015 an attack in front of a central station in Ankara claimed by the Islamic State group killed 109 people.
The most recent bomb attack in Turkey was in a shopping street in Istanbul in November 2022, where six were killed and 81 were injured.
There was no claim of responsibility, but Turkey accused the outlawed PKK of being behind the attack and said it had detained 46 people including a Syrian woman suspected of planting the device.
The bombing took place in the popular shopping street of Istiklal Avenue on a Sunday afternoon.
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