Russian, Norwegian couple joined ISIS; widow returned to Turkey illegally and carried out suicide bombing in Istanbul.

The young woman from the Russian Muslim region of Dagestan suspected of carrying out a deadly suicide bombing in Istanbul last Tuesday was the widow of a Norwegian extremist, with whom she had traveled to Syria to join Islamic State (ISIS) jihadists, a report said Friday.

A policeman and the suicide bomber were killed in the attack on January 6 in Sultanahmet, the heart of Istanbul's tourist district and home to its greatest concentration of historic monuments, according to AFP.

The Turkish authorities have so far refrained from naming the suicide bomber but reports in Turkey and Russia identified her as Diana Ramazanova from the northern Caucasus region of Dagestan.

The Hurriyet daily said she was the widow of a Norwegian citizen of Chechen origin, Abu Aluevitsj Edelbijev. She had married him in 2014 in a religious ceremony, either in Istanbul or in Syria.

In July 2014 the pair crossed the border from Turkey into Syria, joining ISIS jihadists who have seized large parts of Syria up to the Turkish border.

He took the name of Idris while she became known as Sumeyra, it said.

Edelbijev was killed while fighting in December. Ramazanova then crossed the border illegally back into Turkey on December 26, before carrying out the suicide bombing in Istanbul on January 6.

Hurriyet said security services are still trying to ascertain whether she brought her explosives with her from Syria, or whether they had been given to her by a contact in Istanbul.

If confirmed, the newspaper's information would for the first time make a clear jihadist link to the Istanbul suicide bombing.

A radical outlawed Marxist group had initially caused confusion by claiming the attack, but then retracted the claim saying it made a mistake.

Both Russian media and Hurriyet published pictures of Ramazanova before she was married, showing a seemingly normal Russian girl who took good care of her appearance and wore short dresses.

Without specifying the source of the images, Hurriyet also published pictures it said were of the pair with fellow jihadists in Syria.

Russian newspaper Kommersant reported on Thursday that the local security services in Dagestan also believed Ramazanova had carried out the bombing, adding she was aged only 18.

Tabloid news site lifenews.ru cited acquaintances of Ramazanova in Dagestan as saying she had totally changed after meeting her extremist husband on a social networking site.