Singapore Prime Minister Lee Hsien Loong has written to Indonesian President Joko Widodo to convey his condolences over the military plane crash in Medan.
"I was saddened to hear of the tragic crash of the military plane in Medan,'' Mr Lee said in the letter dated July 2, according to the Ministry of Foreign Affairs (MFA).
"On behalf of the Government of the Republic of Singapore, I extend our deepest condolences and sympathies to the families who lost their loved ones in this tragedy. Our heartfelt sympathies also go to those who were injured in this tragic accident,'' he added.
Singapore Deputy Prime Minister and Minister for Home Affairs Teo Chee Hean and Minister for Defence Ng Eng Hen have also sent letters to their Indonesian counterparts to express their sympathies, said MFA.
The Indonesian military plane - a Hercules C-130 - crashed into a residential neighbourhood in Medan city on Tuesday and exploded into a fireball. There were 122 people aboard the plane, mostly servicemen and women and their families. There were also fatalities on the ground.
The Indonesian air force said the plane likely suffered an engine failure, Agence France-Presse reported. Air Vice-Marshal Agus Dwi Putranto, an air force operations commander, told reporters on Thursday that initial findings indicated the 51-year-old transport plane had failed to gain enough speed after one of its four engines malfunctioned.
"There's a likelihood that a propeller had stalled," he was quoted as saying. "Going at a slow speed, the plane swerved to the right and hit an antenna tower."