ATHENS, Greece (AP) — Greek authorities declared a state of emergency on the island of Lesbos on Tuesday, a day after an earthquake killed one woman and displaced more than 800 people.

The 6.2-magnitude undersea quake occurred south of Lesbos on Monday, but was felt as far as Istanbul.

Officials from Lesbos' regional government said that homes in 12 southern villages had been seriously damaged or destroyed. The mostly elderly residents affected were being housed with relatives, in hotels or at an army-run shelter.

The earthquake marked the second crisis to hit the island in the last two years, after hundreds of thousands of migrants and refugees, including many fleeing war in Syria and Iraq, crossed to Lesbos on boats from Turkey as they headed to Europe.

Seismologists in Greece and Turkey said the quake had been followed by a typical pattern of aftershocks. But one prominent politician in Turkey claimed the temblor may have been an act of sabotage by "external powers."

In a series of tweets Monday and Tuesday, Ankara Mayor Melih Gokcek claimed that the quake may not have occurred naturally, noting that the U.S., Israel and neighboring Greece cooperate on seismic research.

"Now, I think this earthquake could be an artificial earthquake. I'm not saying it's definite, but it's a serious possibility," Gokcek said.

"The power of outside forces wasn't strong enough for Turkey until now. However, they may play the artificial earthquake card to finish us economically and politically."

Gokcek, a veteran politician, has 3.8 million followers on Twitter. He has claimed in the past that Turkey could be targeted by maliciously-generated earthquakes, offering little further explanation.