"If, as we all hope, they are reunited with their families in the coming days and their health allows them to travel, Federation Internationale de Football Association would be delighted to invite them to attend the 2018 World Cup final in Moscow as our guests".
Between four to six boys have been rescued in the first phase of the operation to free the trapped soccer team, Thai officials told reporters.
The operation to remove the boys could take three or four days, Third Region Army Deputy Commander Supachoke Thawatpeerachai said.
In letters written by the boys released Saturday, the boys appeared calm and reassured their families they were "fine".
The dozen boys between the ages of 11 and 16 are accompanied by their 25-year-old coach.
With them were five other global divers and five Thai navy SEALS, and more than 70 other divers in support roles, 50 of whom were foreigners.
"Today is a D-Day for our operation", Narongsak said. The tweets show the submarine being slowly ferried underwater by a team of divers. "At 10 am today (8:30 am IST) 13 foreign divers went in to extract the children along with five Thai navy SEALs". "Everyone is a professional so we're trying to put it away and avoid it happening again", he said, adding: "Everybody is focusing on getting these boys out - keeping them alive or getting them out". Osottanakorn said they will resume in 10 to 20 hours because "we've used all the oxygen". He has also thanked global experts who helped find the boys.
"The water level may rise to the area where the children are sitting and make the area less than 10sq meters", Narongsak said, citing estimates from cave divers and experts.
Officials had looked at many different ways to save the boys and their coach.
More than 100 exploratory holes were also bored - some shallow, but the longest 400 metres deep - into the mountainside in an attempt to open a second evacuation route and avoid forcing the boys into the risky dive.
The boys have been trapped for more than two weeks in the cavern, as waters have been rising from the monsoon rains. They were escorted out by a group of Thai and worldwide divers. Musk said based on "feedback from Thailand", the engineers made a decision to build a "tiny, kid-size submarine" using a large silver tube meant to be affixed to a SpaceX Falcon 9 rocket.
In one, Pheerapat, nicknamed "Night", whose 16th birthday the group were celebrating in the cave when they became stuck on June 23, said: "I love you, Dad, Mum and my sister. You don't need to be anxious about me".