The BBC has expressed concern after one of its journalists was targeted in a "threatening" Twitter campaign by a senior Turkish politician over her coverage of protests in the country.

The BBC Turkey reporter Selin Girit was accused of "treachery" and acting as a foreign agent in a series of tweets by Ibrahim Melih Gökçek, the longstanding mayor of Ankara, on Sunday.

The corporation said the 24-hour Twitter campaign was prompted by its coverage of the uprising against the Turkish prime minister, Recep Tayyip Erdoğan.

Peter Horrocks, BBC global news director, said he was "very concerned" by the Turkish authorities' attempts "to discredit the BBC and intimidate its journalists".

In a statement on Monday, Horrocks said: "A large number of threatening messages have been sent to one of our reporters, who was named and attacked on social media by the mayor of Ankara for her coverage of the current protests.

"The BBC and all its journalists are committed to providing impartial and independent journalism. It is unacceptable for our journalists to be directly targeted in this way. There are established procedures for making comments and complaints about BBC output and we call on the Turkish authorities to use these proper channels."

Gökçek is a member of Erdoğan's ruling Justice and Development party (AKP), which has become the focus of protests in and around Istanbul since 28 May.

In a stream of tweets targeting the BBC reporter, he asked: "Who is @selingirit? BBC's reporter in Turkey. Led by England, they are trying collapse our economy via agents hired, both nationally and internationally. They are dreaming for Turkey to be the 'Sick man of Europe' once again. Here is a concrete proof."

He asked his nearly 700,000 followers to "show their democratic reaction" to Girit and attempted to popularise the Turkish hashtag "#INGILTEREADINAAJANLIKYAPMASELINGIRIT", roughly translated as: "Don't be a spy in the name of England Selin Girit."

The campaign against Girit drew condemnation from the International Federation of Journalists, whose president, Jim Boumelha, urged Turkish authorities to "stop targeting and intimidating journalists and allow them to report protests without fear and censorship".

The Turkish branch of the BBC's National Union of Journalists (NUJ) chapel also issued its public support for Girit. Michelle Stanistreet, NUJ general secretary said: "We want to send a strong message to Turkish authorities – it is simply not acceptable to target journalists in your turbulent times.

"We condemn the attempts to intimidate journalists and the threats must stop immediately. Those who are responsible for the attacks need to back off. The freedom of the press is essential for all Turkish citizens and the rest of the Turkish people around the world – we need journalism in the public interest and we want to know about Turkey."

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