Turkey says it arrested six ISIS supporters planning attack on giant protest march

Turkish police on Wednesday detained six suspected members of ISIS planning a bomb attack on an opposition protest march, a provincial governor told Turkish media.

Republican People's Party (CHP) leader Kemal Kilicdaroglu is on the final stage of a 450-kilometre (280-mile) "justice march" from Ankara to Istanbul to protest at the legal system under President Recep Tayyip Erdogan. 

Every day, thousands of people have accompanied Kilicdaroglu, who plans to finish the march with a mass rally in Istanbul on Sunday.

Suleyman Kamci, who governs the central Anatolian province of Kayseri, said police detained six IS militants after "acting on a good tip-off", the Hurriyet daily's website reported. 

"They were going to attack the march with a minibus," he said. "A big provocation has been thwarted." There was no immediate confirmation from national officials. 

Two of the would-be bombers were detained in Kocaeli in northwestern Turkey — 100 kilometres (60 miles) from Istanbul and four others in Kayseri, Hurriyet said. 

The governor said the suspects had put flags from the ruling Justice and Development Party (AKP) in the minibus to give the impression the government was somehow involved. 

Police have heightened security around the march following the latest detentions, Hurriyet said. 

CHP spokesman Bulent Tezcan played down the detentions, saying they were part of "routine work" by the security forces. 

"We are working to let the march take place in a safe environment despite all kinds of attempted provocations," he said. 

"Each passing day the participants are increasing. I believe it will get even bigger when we approach Istanbul."