Ankara Metropolitan Municipality Mayor Melih Gökçek has warned that foreign countries might be planning to trigger an artificial earthquake in Turkey’s Marmara region to cause economic destruction in the country.

Writing from his Twitter account on Tuesday, Gökçek voiced his concerns about an artificial earthquake in the wake of several tremors, all greater than magnitude five, which hit Turkey’s west coast around Çanakkale province on Monday and Tuesday.

“A serious earthquake hit Çanakkale today. I searched it a little bit and found out that there is a ship in the environs doing seismic research. It should immediately be found out which country this ship belongs to and what it is searching for. No matter who says what, I am seriously concerned about the triggering of a potential earthquake,” Gökçek wrote.

He said there are efforts to lead Turkey into economic destruction by triggering an earthquake around İstanbul.

“All the submarines and ships with heavy equipment around İstanbul, Marmara and Çanakkale should be kept under control,” Gökçek wrote.

In August, Gökçek made a similar warning and said the faith-based Gülen movement, which is accused by the government of masterminding a failed coup attempt on July 15, would trigger an earthquake in the country.

On Tuesday, he also wrote that his warning in August had foiled the Gülen movement’s plans to trigger an artificial earthquake.