Two Russian journalists from Russian TV channel NTV were arrested in Istanbul, the channel said.
Two Russian journalists were arrested by police in Turkey, according to the TV channel they work for.
In a statement on Friday, television channel NTV said journalists Alexei Petrushko and his cameraman Ivan Malychkin “informed the editorial staff that they had been arrested by police...in Istanbul”.
They were still being held on Thursday evening, according to a message sent by Petrushko and quoted by the station.
Both work for the programme Tsentralnoïe televidenie, which positions itself as a weekly news show.
The journalists have not answered the phone or messages since then, according to the statement.
According to a source in the Turkish Foreign Ministry, the journalists were arrested as they were “filming a drone factory without any accreditation”.
“They arrived in Istanbul for filming, but have received neither permission nor accreditation” to film, the source told AFP.
The office of the governor of Istanbul announced on Friday evening that the duration of police custody of the journalists had been extended by three days and that the investigation about them was underway.
For its part, the Russian embassy in Turkey said it was in contact with the Turkish authorities to clarify the situation.
“We are counting on operational cooperation” on the Turkish side, the embassy said in a statement published on its Facebook page.
The arrest comes at a time when Turkey, a staunch supporter of Azerbaijan, announced this week an agreement with Russia on the establishment of a joint observation centre to monitor the ceasefire in Nagorny Karabakh, a separatist Azerbaijani enclave populated mostly by Armenians.
Fighting between Azerbaijani forces and Armenian separatists, which broke out at the end of September in this region, has led to several thousand deaths in six weeks.