Counter-terrorism teams launched raids in three Turkish cities yesterday, seizing firearms and arresting suspected Isis militants as the Turkish military deployed troops and firepower to the volatile border with Syria.
Police raided 22 properties in eastern Erzurum and the coastal cities of Izmir and Isparta, according to local media reports, arresting seven militants.
Pistols, rifles, Isis flags and "organisational documents" were discovered during the raids. The operation came just days after the Isis attack in Tunisia.
"That kind of attack could happen in Turkey tomorrow," said Aaron Stein, a Turkey expert and Associate Fellow at the Royal United Services Institute.Stein added: "That would be the end of tourism in Turkey, which is so important to the country."
Izmir and Isparta are popular with travellers, situated on the country's western tourism trail.
Dogan News Agency reported the seven militants had been involved in the four-month Isis siege of Kobane in northern Syria.
It is believed they fled across the border as the city's Kurdish defenders, backed by US-led coalition air strikes, drove the militants from the city in late January.
Ankara has grown increasingly concerned at the Isis presence on its border. Sleeper cells are believed to be spread throughout the country.
While evidence suggests Ankara has previously collaborated with Isis, the relationship has broken down over the past 18 months.
"The gentleman's agreement between the Islamic State and Turkey has started to fray," said Stein. A black widow suicide attack in Istanbul's Sultanahmet tourist district this year coupled with a large number of Turkish Isis fighters returning home had widened the rift.
Turkey has stacked entry points - airports, land crossings, bus terminals - with police officers. Authorities claim to have refused entry to more than 7000 would-be militants, detaining and deporting scores more.
Police last week arrested a further 12 suspected Isis fighters in the southeastern Turkish city of Kilis, about 10km from the important Turkey-Syria border crossing of Bab al-Salameh.
Turkey's military reinforced a 100km stretch of border yesterday with tanks, armoured combat vehicles and military personnel, Anadolu News Agency reported.