The young Thai soccer players rescued from a cave paid a tearful tribute on Sunday to the former Thai navy SEAL who died while taking part in their rescue mission.

The boys – ranging in age from 11 to 16 – expressed their condolences by penning thoughtful messages on a drawing of Lieutenant Commander Saman Kunan from the Chiang Rai hospital where they are recovering after their 18-day ordeal.

Images released by the Thai Public Health Ministry showed the Wild Boars soccer team with their eyes closed and heads bowed as they observed a minute of silence for the volunteer rescue diver, who perished on July 6 when he ran out of his own air while placing air tanks throughout the Tham Luang cave.

One photo showed a boy wiping his eyes with his hospital gown as he mourned the fallen frogman.

The boys were only told of Saman’s death on Saturday after a medical team said they were strong enough to handle the grim news, and they cried upon hearing it, Channel News Asia reported.

“All cried and expressed their condolences by writing messages on a drawing of Lieutenant Commander Saman and observed one minute of silence for him,” Jedsada Chokdamrongsuk, permanent secretary at the health ministry, said in a statement.

“They also thanked him and promised to be good boys.”

Tributes from around the world have poured in for the widely-hailed hero – with a local artist recently announcing he would use his own money to build a large statue of the ex-SEAL.