ISTANBUL (Reuters) - The mayor of Ankara suggested on Tuesday that the U.S.-based cleric blamed for last year’s failed coup might now be plotting an earthquake, with the help of foreign powers, to damage the Turkish economy.

FILE PHOTO: U.S. based cleric Fethullah Gulen at his home in Saylorsburg, Pennsylvania, U.S. July 29, 2016. REUTERS/Charles Mostoller/File Photo

Melih Gokcek said investigations needed to be carried out on a “seismic vessel” which had been in the vicinity of the Aegean coastal town of Canakkale on Monday when a small earthquake struck, the latest in a series of tremors in recent days.

“No matter what they say, I’m still worried about the possibility of an artificial earthquake,” he wrote on Twitter, adding that the “Gulenist Terrorist Organisation” (FETO) had planned an earthquake before.

“Their plan was failed after the strategy was disclosed to the public on that time. But currently they are trying to originate an economic crisis with the help of the major earthquake (artificial),” he wrote in English.

Turkey blames the network of Muslim cleric Fethullah Gulen for last July’s failed coup, in which almost 250 people were killed as soldiers commandeered tanks and fighter jets in a bid to seize power. Gulen denies involvement.

Conspiracy theories have spiced up Turkish crises for decades, with the United States and its Western allies often accused of being the hidden hand. President Tayyip Erdogan has cast recent economic weakness as part of a foreign plot.

Turkey is criss-crossed by geological fault lines and frequently suffers tremors and earthquakes.

Pro-government commentator Omer Turan said FETO and “deep NATO” - which he defined as the United States and Britain - may have been behind the recent earthquakes as part of what he called a “multi-dimensional” coup plot.

“Look at the earthquake activity in the Aegean in the last month and analyse it with an honest seismologist. You will see that it is definitely not normal,” he wrote on Twitter, where he has almost 100,000 followers.

“Deep NATO and its chief pawn FETO has the option of an artificial earthquake in the multi-dimensional and gradual chaos coup process which they have planned for Turkey,” he said.