ANKARA, Turkey (AP) — Turkish authorities on Monday detained 10 former admirals after a group of more than 100 retired top navy officers issued a midnight statement that government officials tied to Turkey’s history of military coups.

The 10 retired admirals were detained as part of an investigation, launched by the chief prosecutor in Ankara on Sunday, over suspicions that they had reached “an agreement with the aim of committing a crime against the security of the state and the constitutional order,” the state-run Anadolu Agency reported.

Four others were not detained because of their advanced ages but were asked to report to the authorities within three days, Anadolu reported.

A total of 103 retired admirals signed the statement declaring their commitment to an international treaty that regulates shipping through the Bosporus and Dardanelles straits, which link the Mediterranean Sea to the Black Sea. The 14 suspects are believed to have organized the declaration.

The statement was issued amid a debate over whether Turkish President Recep Tayyip Erdogan, who withdrew Turkey from a international convention to protect women last month, could also pull the country out of the 1936 Treaty of Montreux, which regulates the passage through the straits, and other international treaties.

Erdogan’s plans to build an alternative waterway to the north of Istanbul that would bypass the Bosporus, had also sparked debate over the Montreux treaty.

“The fact that withdrawing from the Montreux Convention was opened to debate as part of talks on Canal Istanbul and the authority to exit from international treaties was met with concern,” the retired admirals said in a declaration released late Saturday.

The statement triggered strong condemnation by ruling party and government officials who drew a parallel with statements that accompanied past military takeovers in Turkey.

Turkey experienced coups in 1960, 1971 and 1980, and a 1997 military intervention caused the resignation of an Islamist-led coalition government. In 2016, a failed coup led to more than 250 deaths.

Anadolu reported that those detained include Cem Gurdeniz, the name behind Turkey’s controversial “Blue Homeland” doctrine, which claims vast sections of the Mediterranean and Aegean and its undesea energy deposits. The concept is at odds with Greece and Cyprus’ claims in the region.

The suspects were detained at their homes in Ankara, Istanbul and Kocaeli, and were to be questioned by the chief prosecutor’s office in the capital.