ISTANBUL (AFP) - Turkish shares plunged nearly 5 per cent on Thursday after Prime Minister Recep Tayyip Erdogan dug in his heels anew against a mass protest movement challenging his leadership.

The Istanbul stock market's main index closed 4.7 per cent lower after dipping as much as 6.5 per cent immediately after Mr Erdogan's comments, ahead of his return to Turkey from a trip to Tunisia.