ISTANBUL (AFP) - Around 3,000 people in Turkey are believed to be linked to the Islamic State in Iraq and Syria (ISIS) militant group, a Turkish intelligence report said on Saturday, warning of possible attacks by extremists.

The report called for enhanced surveillance of the 3,000 people, including identifying their rank within the extremist group or whether they were active within it, the Hurriyet newspaper reported on Saturday.

A "red alert" had also been sent to security units warning of possible attacks on the embassies of Western countries by ISIS fighters following last week's deadly Islamist attacks in France, the report said.

Security at the diplomatic missions had been increased to the maximum level, the report said, adding that Nato facilities and Western nationals were also potential targets.

And it warned of possible bomb attacks "anywhere and anytime" in Turkey by "sleeping cells". Most of the vehicles stolen in Turkey ended up in the hands of ISIS hardliners, it said, warning that they could be used in car bomb attacks in the country.

Turkish Foreign Minister Mevlut Cavusoglu on Thursday said up to 700 Turkish nationals had joined the ISIS.

He added that Turkey had barred entry to around 7,250 people from abroad who were planning to join ISIS and said 1,160 would-be extremists were also deported.

Turkey has long been accused of not doing enough to stem the flow of Islamists seeking to join the ISIS group which has captured large swathes of territory in Syria and Iraq.

The Turkish government said on Monday that Hayat Boumeddiene, the wanted partner of one of the gunmen involved in last week's Paris attacks, crossed into Syria via Turkey days before the assaults, amid reports that she may have joined ISIS.

A female suicide bomber killed herself and a policeman last week in Istanbul's Sultanahmet district, home to the city's greatest concentration of historical monuments.

Turkish authorities have so far refrained from naming the suicide bomber but reports in Turkey and Russia on Friday identified her as Diana Ramazanova, 18, from the northern Caucasus region of Dagestan.

She was said to have been the widow of a Norwegian Islamist who died fighting for ISIS in Syria.