Turkish police detained six suspected Islamic State militants for planning to attack a three-week-old protest march led by the head of the main opposition party, a provincial governor was quoted as saying on Wednesday.
Tens of thousands of people have joined the opposition CHP leader Kemal Kilicdaroglu on his 425-km (265-mile) march from the capital Ankara to Istanbul, a protest launched after a deputy from the secularist CHP was jailed on spying charges.
Kilicdaroglu, 68, said there had been rumours his "justice march", which has grown into a wider anti-government protest, could be targeted by "provocations" as it approached Istanbul, where it is set to end with a mass rally on Sunday.
"Following a nice tip-off, our police detained a group of six Islamic State militants. They were planning to attack the convoy with a minibus," Kayseri Governor Suleyman Kamci told the website of Hurriyet newspaper. Kamci did not specify what sort of assault was allegedly planned. Islamic State (IS) has carried out both bomb and gun attacks in Turkey in the past.
Police and officials declined to comment but state-run Anadolu news agency carried a similar report. Kamci said the suspects rented a black minibus in Kayseri on Tuesday, and that four of them were subsequently detained in Kayseri and two in Kocaeli province, through which the protesters were marching on Wednesday.
A video purporting to show part of the police operation and published on Turkish news websites showed officers, some with assault rifles, storming a black minibus waiting in traffic on a main highway and then leading away at least one man.
Flags of the ruling AK Party were found in the minibus, Kamci said. Turkish media said earlier that police had detained 37 IS suspects in anti-terrorism operations in provinces across the country, while officials said another suspect was arrested at the border with Syria while carrying more than 5 kg (11 lb) of explosives.