Turkish Government says eight people have been detained in connection with the deadly weekend attack on an Istanbul nightclub and it is close to identifying the man responsible for the assault.

At least 39 people, including 16 foreign nationals, mostly from Middle East, were reportedly killed in the attack.  A Russian woman is among the victims, according to Russian state news agency TASS.

Among those killed are also the citizens of Saudi Arabia, Morocco, Lebanon, Jordan, Libya and Israel.  A total of 65 people have been hospitalized and four of them are in critical condition, Turkish Health Minister Recep Akdag said.

The Islamic State (IS) militant group has claimed responsibility for the attack. 

Turkish authorities said they were close to identifying the killer using fingerprints and the grainy black and white images from security footage as he entered the club firing on the crowd of 600.

ABC reports that police said they arrested eight people, from towns about two hours south of the nightclub, in connection to the attack but stressed the gunman was not one of them.

Deputy Prime Minister Numan Kurtulmus confirmed the arrests but did not provide more details, saying a “sensitive” investigation was underway.

Authorities had obtained the fingerprints and a basic description of the gunman and were close to identifying him, Mr. Kurtulmus said.

Earlier, Turkish media reports said that Turkish authorities believed the IS group was behind the attack and that the gunman was likely to be either from Uzbekistan or Kyrgyzstan.

According to the Hurriyet and Karar newspapers, police had also established similarities with the high-casualty suicide bomb and gun attack at Istanbul's Ataturk Airport in June and were investigating whether the same IS cell could have carried out both attacks.

Meanwhile, Kyrgyzstan's Foreign Ministry said it was looking into the media reports.

“We have ordered the consul in Istanbul the check this report that has appeared in the press,” the Interfax news agency quoted ministry spokeswoman Aiymkan Kulukeyeva as saying.

“According to preliminary information, this information is doubtful but we are checking all the same.”

The gunman killed a policeman and another man outside the Reina club in the early hours of 2017 before entering and firing with an automatic rifle at an estimated 600 people partying inside.

Nearly two-thirds of the dead in the upscale club, which is frequented by local celebrities, were foreigners, Turkey's Anadolu agency said.