UPDATE: 7:26 a.m. EST — Turkey’s Deputy Prime Minister Numan Kurtulmus said Tuesday that the suicide bomber responsible for the blast at Istanbul’s Sultanahmet Square was a 28-year-old Syrian, the Associated Press reported, adding that most of the victims were foreigners. Kurtulmus said that two of the 15 wounded were seriously injured.

UPDATE: 6:46 a.m. EST — Turkish President Recep Tayyip Erdoğan said Tuesday that Turks and foreigners were among those killed in an explosion in Istanbul. "I condemn the terror incident in Istanbul assessed to be an attack by a suicide bomber with Syrian origin. Unfortunately we have 10 dead including foreigners and Turkish nationals. ... There are also 15 wounded," Erdoğan said, in a speech broadcast live on television, Reuters reported.

RTX21Z6X Police secure the area after an explosion in central Istanbul, Turkey Jan. 12, 2016. Photo: REUTERS/OsmanOrsal

UPDATE: 6:39 a.m. EST — Turkish President Recep Tayyip Erdoğan said Tuesday that a Syrian suicide bomber is believed to be responsible for the explosion at a central Istanbul square popular with tourists, according to media reports. Previously, two senior Turkish security officials told Reuters that there was a high probability that Islamic State group militants were responsible for the blast that killed at least 10 people.

UPDATE: 6:12 a.m. EST – Turkish security officials believe that an ISIS-linked suicide bomber was behind Tuesday’s explosion at a central Istanbul square that killed at least 10 people, Hurriyet Daily News reported.

GettyImages-504660614 Turkish police secure the area after an explosion in the central Istanbul Sultanahmet district in Istanbul, Turkey, Jan. 12, 2016. Photo: Can Erok/Getty Images

UPDATE: 5:57 a.m. EST – At least six German nationals, one Norwegian and one Peruvian are among those injured in Tuesday’s explosion in Istanbul, the Guardian reported, citing Turkey’s Dogan news agency.

UPDATE: 5:31 a.m. EST – One Norwegian and two German nationals are reportedly among those injured in Tuesday’s explosion at a central Istanbul square, Reuters reported, citing Turkey's CNN Turk television.

Germany’s Foreign Ministry warned its citizens to avoid crowds outside tourist attractions in Istanbul following the explosions. However, it did not confirm reports that Germans were among the casualties. The ministry also said that “terrorist attacks” are expected across Turkey, the Guardian reported.

RTX220IA Police forensic officers attend the scene after an explosion in front of the German Fountain in Sultanahmet Square in Istanbul, Turkey Jan. 12, 2016. Photo: REUTERS/Murad Sezer

UPDATE: 5:09 a.m. EST – A local report stated that the country's Radio and Television Supreme Council (RTÜK) had a imposed a temporary ban on the media's coverage of the explosion following a demand from the prime minister's office.

A journalist for Euro News also posted about the development on his Twitter account.

UPDATE: 4:56 a.m. EST – German tourists were among the casualties in the explosion that struck Istanbul’s historic Sultanahmet district, local media Radikal reported.

A statement from the Istanbul governor’s office reportedly said that investigators are trying to determine the cause and type of explosion in the popular tourist area. AFP reported earlier that officials suspect a terror link in the incident.

UPDATE 4:50 a.m. EST – A Turkish official said that authorities suspect a terror link in Tuesday’s explosion at a central Instanbul square that killed at least 10 people, Agence France-Presse reported on Twitter.

UPDATE: 4:38 a.m. EST – At least 10 people were killed and 15 others injured after an explosion rocked a central Instanbul square Tuesday, the Associated Press reported, citing Istanbul’s governor’s office.

Turkish Prime Minster Ahmet Davutoğlu is set to hold an emergency meeting following the blast, local media reported.

Meanwhile, an official at the South Korean consulate general said that one of those injured in the explosion is a South Korean citizen, Yonhap news agency reported.

UPDATE: 4:26 a.m. EST – At least eight people have been killed and several others injured by an explosion Tuesday at a central Instanbul square that is popular with tourists, Turkey's Haberturk television reported.

Original story:

An explosion at a central square in Turkey’s biggest city, Istanbul, was reported by Turkish media Tuesday. The incident reportedly took place in the city's historic Sultanahmet district.

Turkey's local Dogan news agency reported that several people were injured in the explosion, and police have sealed off the area. According to reports, ambulances rushed to the scene of the explosion — close to the Blue Mosque and Hagia Sophia — two major tourist attractions in Istanbul, and the wounded were taken to local hospitals.

Erdem Koroglu, who was working at a nearby office at the time of the explosion, told local NTV television that he saw several people lying on the ground following the blast.

“It was difficult to say who was alive or dead,” Koroglu said, the Associated Press reported. “Buildings rattled from the force of the explosion.”

The cause of the explosion was not immediately clear, though, Al Jazeera reported that Turkish police suspect the explosion to be the result of a suicide bombing.

Turkey has witnessed two major bombings last year, and has also endured a number of security threats in recent months.

In July, more than 30 people were reportedly killed in an ISIS suicide attack in the town of Suruc, near Turkey’s border with Syria. In October, two suicide bombs outside Ankara’s main train station during a peace rally killed over 100 people. Authorities reportedly said that the attack in Turkey's capital city was the deadliest attack, which was carried out by a local ISIS cell.