Turkey is stepping up its role in the fight against Islamic State extremists after realising the threats to its own security from jihadists and responding to pressure from its Western partners, analysts say.
Turkish security forces have over the last week arrested dozens of IS militants and sympathisers, in its most significant raids since the group began to seize swathes of neighbouring Iraq and Syria in 2014.
Turkey has faced bitter accusations it was not doing enough to halt the rise of IS and even secretly colluding with the group -- allegations Ankara vehemently denies.
But analysts say the Turkish authorities have now clearly understood the domestic threat posed by IS, which rules its territory under a harsh version of Islamic law known for its brutality.
Ankara will also get nowhere in trying to prevent the Kurds, who have been battling IS in northern Syria, from establishing their own autonomous region there unless it supports the Western coalition against the jihadists.
Turkey sees the main Syrian Kurdish political group the Democratic Union Party (PYD) and its military wing, the People's Protection Units (YPG), as offshoots of the Kurdistan Workers' Party (PKK), which has fought a decades-long insurgency in its southeast.
"Turkey has realised that it would not receive any support from its allies... to prevent the creation of an autonomous Kurdish area on its border if it failed to respond to their harsh criticism on the fight against ISIS," said Sinan Ulgen, chairman of the Istanbul-based think-tank EDAM, using a variant name for IS.
Ankara in the past used IS as a tool to achieve its goals in the region, from battling the regime of President Bashar al-Assad in Syria to containing Kurdish influence, the former Turkish diplomat told AFP.
But Turks now see that "they are in the frontline, risking retaliation from the jihadists themselves," said Ulgen, adding: "They still cannot control their borders and fear IS members may slip through its soil among refugees."
Turkish authorities have always pointed to the challenge of controlling a 911 kilometre (566 mile) border with Syria while remaining open to the refugees fleeing the fighting, as well as 38 million tourists a year.
But its failure to halt many IS recruits travelling to Syria through Turkish soil -- including Hayat Boumeddiene, the partner of one of the gunmen in January Paris shootings -- has piled pressure on Ankara.
In recent weeks, Turkey launched a series of raids against IS suspects in cities across the country, from Izmir on the Aegean to Gaziantep close to the Syrian border.
A Turkish official told AFP the raids targeted the group's sleeper cells and networks inside the country.
Last Friday, police arrested 29 suspected IS members in Istanbul and other cities for "directing citizens of European countries seeking to join Daesh operations to Syria and Iraq," said the official, using another name for IS.
The raids came just after a senior US delegation visited Turkey, NATO's only majority Muslim member, to demand more cooperation from Ankara in its campaign against IS.
"It's now obvious that the Turkish government has upgraded the threat posed by ISIS to among the top ones it is facing, roughly at the same level as the PYD/YPG one," a senior Western diplomat told AFP.
"It's a reassessment we've been expecting for a long time."
But the Turkish official denied any policy change, saying that Ankara "has successfully curbed the influx of foreign terrorist fighters into the region" as a result of army measures to secure the border and by sharing more intelligence with allies.
Turkey has deported more than 1,500 IS suspects and banned nearly 15,000 individuals from 98 countries from entering the country, according to the official, who added that Ankara had categorised IS as a terrorist group since October 2013.
Some sources, however, cast doubt over the significance of the latest steps.
Turkey has still not given the United States the green light to use the Incirlik air base in the south of the country as a launchpad for bombings against IS targets.
"This is not a fundamental policy shift, it is mainly circumstantial," another Western source familiar with the matter told AFP.
The source argued the raids "targeted only very low-profile ISIS members" and came at a time when "the US is putting a lot of pressure" on Turkey to cooperate more.
Max Abrahms, professor of political science at Northeastern University and a member at the US Council on Foreign Relations think-tank, said Turkey's latest steps were "welcome" but also "way too little, way too late".
"From the US perspective, Turkey has been a massive disappointment in helping to combat Islamic State," he said in emailed comments.