In his latest attack on journalists, Turkish President Recep Tayyip Erdogan has threatened to make a newspaper editor "pay a high price" after his paper published images of what it said were Turkish trucks loaded with ammunition destined for militant groups in Syria.

Last week, the Cumhuriyet daily published alleged photos and video from January 2014 when local authorities searched Syria-bound trucks, touching off a standoff with Turkish intelligence officials. Cumhuriyet said the images were proof that Turkey was sending arms to Syrian rebels — a claim the government rejects.

Cumhuriyet's chief editor, Can Dundar, is under investigation for possible breach of anti-terror laws.

Erdogan accused Dundar in a television interview late Sunday of engaging in "espionage" and said "he will pay a high price. I won't let him go."