ISTANBUL (Reuters) - Turkish police have issued a nationwide warning about possible Islamic State in Iraq and Syria (ISIS) attacks on Thursday's national holiday, state media said, with military facilities seen as targets after the army stepped up attacks on the militants in Syria.
Both ISIS and Kurdish militants have staged bomb attacks in Turkey in recent months, fuelling concern about the spillover of conflict from its southern neighbour.
Turkish and United States-led coalition forces have killed dozens of ISIS fighters in shelling and air strikes in northern Syria after months of rocket fire from ISIS-controlled territory targeted a Turkish border town, killing 21 people.
The police warning, issued to all 81 provincial police forces, said ISIS "viewed Turkish soldiers and police as infidels and fighting and killing them as permissible", state-run Anadolu Agency reported.
It called for a reassessment of security measures for celebrations on May 19, when Turks commemorate the country's founder, Mustafa Kemal Ataturk, and mark what is known as Youth and Sports Day.
Military and police facilities and public buildings were in particular regarded as potential targets, the police said, with media reports singling out Ataturk's mausoleum, Anitkabir, in the Turkish capital.
The armed forces said in a statement the mausoleum would remain open on Thursday, when traditionally thousands of people visit and pay their respects.
The warning also coincides with increased police action targeting ISIS suspects in Turkey.
Turkish police in the eastern province of Elazig raided six addresses and detained seven ISIS suspects including a senior commander of the group, Anadolu said on Monday.
It said the suspects had come from Syria and one of them had carried out executions on behalf of the group there. ISIS documents were also seized during the raids.
A wave of suicide bombings this year, including two in Turkey's largest city Istanbul, have been blamed on ISIS, and two in the capital Ankara were claimed by a Kurdish militant group.