Turkey made 10 arrests on Monday over a letter released by more than 100 retired admirals warning about a possible threat to a treaty governing the use of Turkey’s key waterways.
Prosecutors also ordered four other suspects to report to Ankara police within three days, opting not to detain them because of their age.
The development comes a day after the letter was sharply condemned by the government, which said the move is “reminiscent of coup times” in Turkey’s past.
Ankara’s approval last month of plans to develop a shipping canal in Istanbul, comparable to the Panama or Suez canals, opened up debate about the 1936 Montreux Convention.
Kanal Istanbul (Istanbul Canal) is the most ambitious of what President Recep Tayyip Erdogan calls his “crazy projects”, which have seen him transform Turkey’s infrastructure with new airports, bridges, roads and tunnels during his 18 years in power.
The Montreux Convention guarantees the free passage through the Bosphorus and Dardanelles straits of civilian vessels in times of both peace and war. It also regulates the use of the straits by military vessels from non-Black Sea states.