LIVE UPDATES: Six Dead, 81 Injured as Result of Terror Attack in Istanbul

The General Directorate of Security of Istanbul says the owners of 25 accounts on social networks where provocative publications were published have been identified.

Turkish authorities classify the Sunday explosion in the center of Istanbul as a terrorist attack that was carried out by a woman, Vice President Fuat Oktay said, citing preliminary data.

The blast occurred on the pedestrian tourist street Istiklal on Sunday afternoon. Earlier in the day, Turkish President Recep Tayyip Erdogan said that the death toll from the explosion rose to six.

"We consider it a terrorist act, carried out by a perpetrator, who is believed to be a woman, detonating a bomb, according to preliminary information," Oktay said.

The number of injured people rose from 53 to 81, with two in serious condition, the senior official said.

Oktay pledged that Turkish authorities would promptly investigate the terrorist act and bring those responsible for it to justice.

A Turkish Football Championship match in Istanbul between Besiktas and Antalyaspor ended up being postponed in the aftermath of the explosion that rocked Turkey's capital on November 13.

"It would be wrong to say with confidence that this is a terrorist attack, but preliminary data, CCTV footage and the first information provided by the governor to us indicates that it 'smells like a terrorist attack,'" said Erdogan.

"According to the information that I have received from the city's governor, the death toll is six people at the moment, and the number of injured is 53," the Turkish president said.