The death toll from a strong earthquake in southeastern Türkiye has reportedly surpassed 36-hundred.

According to the U.S. Geological Survey, a seven-point-eight magnitude earthquake occurred at 4:17 a.m. Monday in an inland area 33 kilometers from Gaziantep in the region bordering Syria.

About nine hours later, a second powerful tremor with a magnitude of seven-point-five occurred at a location 59 kilometers north-northeast of Kahramanmaras.

The death toll from the powerful quakes and many aftershocks reportedly surpassed 36-hundred combined in Türkiye and Syria, with about 16-thousand people injured. The number of casualties is expected to rise further as rescue efforts continue.

Turkish President Recep Tayyip Erdogan on Monday declared a seven-day period of national mourning, posting on his Twitter account that the country's flag will be hoisted at half-mast until sunset on Sunday all over the country and in foreign representations.