"We still have to analyze the objects further but we have marked the locations," he said at Tigaras port in Simalungun district, North Sumatra, on Sunday.
The objects are detected 2 kilometers and 2.5 kilometers southwest of the port respectively, he said.
Badan SAR Nasional will ascertain the objects in the two locations before taking further steps, Syaugi said.
The agency will make sure whether one of the objects is the wreckage of wooden built MV Sinar Bangun which sank in Lake Toba on Monday (June 18).
He further praised the local people for their initiative to help search for victims.
According to the standard operating procedure, after the search has lasted for seven days it could be extended for another three days. If after period of time has passed and no indicator was found it can be extended again.
MV Sinar Bangun sank in Lake Toba on June 18 when it was carrying approximately 180 passengers and crew members. Only 18 survivors were rescued, and four bodies were found, while 192 others were listed as missing.
Lake Toba is the world's greatest and deepest volcanic lake in the Earth having a depth of 900 meters, spanning a surface area of 1,145 square kilometers. It is a popular tourist destination in North Sumatra.