President Moon Jae-in on Sunday sent a letter of condolence to Indonesia where a massive earthquake and tsunami killed more than 800 people.

"I cannot suppress my sadness upon the news that the strong quake and tsunami in the Sulawesi region caused massive damage of human life and property," Moon said in the letter sent to Indonesian President Joko Widodo.

"On behalf of the South Korean government and people, I hope those who passed away in the disasters rest in peace and express my sincere condolences for the bereaved families who may be in severe shock and despair over their losses," Moon also said. 

The South Korean president also expressed words of consolation for the Indonesians in the affected region and hoped for successful rescue and search operations.

"I pray that the damage is soon recovered under the leadership of the (Indonesian) president and the people in the region and the whole Indonesia can overcome this situation," Moon said.

The twin disasters swept through the Sulawesi region on Friday, with officials saying the death toll has reached some 830 so far.

Moon returned to Cheong Wa Dae earlier Sunday from his four-day vacation spent at his private home in Yangsan, South Gyeongsang Province.

Following his trip to New York to attend the United Nations General Assembly meeting last week, Moon took time off starting on Thursday.

There, he visited the grave of his father after he missed the traditional ritual during the Korean traditional Chuseok holiday because of his New York trip. 

Cheong Wa Dae released a photo and video clip showing Moon taking a walk around a forest and a reservoir wearing running shoes in rainy weather during the weekend vacation. (Yonhap)