Istanbul: Turkish security forces are searching for four suspected members of the Daesh terror group thought to have entered the country from Syria to carry out attacks, local media said Saturday.

The four, including a German woman, reportedly belong to the same group as the suicide bombers who struck in Ankara earlier this month, killing 102 people in the deadliest attack in modern Turkish history.

As Turkey gears up for November 1 polls, security forces fear the four are preparing a major attack “such as hijacking a plane or a vessel or detonating suicide bombs in a crowded location”, Anatolia news agency said, citing security sources.

Photographs of fake Turkish identity cards allegedly being used by the suspects were published by national media, which said the woman was born in Kazakhstan but had a German passport.

One of the identity cards was said to belong to Omar Deniz Dundar, who had previously been identified by the media as one of the two suicide bombers in the Ankara attack — though other reports had suggested the bomber was foreign.

The second bomber was officially identified this week as Younus Emre Alagoz, brother of the man suspected of carrying out an attack in Suruc on the Syrian border in July, which left 34 people dead.

Prosecutors on Monday held four people suspected of playing a role in the Ankara attack and said they had discovered a cache of suicide vests, Kalashnikovs and hand grenades suggesting there were plans for further bombings.

The Ankara attack has raised political tensions to new heights as Turkey prepares for the November 1 election, in a country that has become more polarised than ever.

Pressure has piled on President Recep Tayyip Erdogan, with opposition figures blaming him for security lapses over the Ankara bombing and failing to crack down on Daesh.