Rescue workers in Thailand have now resumed the search for 12 missing children and their football coach who are lost in a system of caves near the border with Myanmar. The boys, who've not been seen since Saturday, are thought to have been trapped by fast rising waters in the tunnels. But the rescue effort has been severely hampered by heavy rain and concern is growing as time ticks on. Tony Cheng reports from Northern Thailand.  

Thai rescue workers head into Tham Luang cave on Monday to try and locate the missing boys. At the mouth of the cave, their bicycles remain chained up. A sole pair of football boots waiting for its owner to return. For the parents, it's been a harrowing and frustrating wait. In anguish one of the mothers calls for her son to come out. I'll be waiting she says. Outside more gather, anxious for news and praying for the return of their kids.

NAMHOM BOONPIAM MOTHER OF 13 YEAR OLD MONGKOL BOONPIAM "I hope that they are safe. I still have hope. I hope that all 13 of them will be out."

As the day wore on however, no luck. An elite team of Navy seals managed to penetrate most of the cave system, but even they got lost for several hours. As the night drew in, heavy rain hampered the search, which was eventually called off.

TONY CHENG MAE SAI NORTHERN THAILAND "The rescue effort has now been suspended. At one stage this evening they were trying to pump water out of these caves, but the heavy rains, the water dripping through and filling up the rivers that run through here as quickly as they're emptying water out. But they say they'll be back 1st thing tomorrow morning."

Frustration amongst the rescue services too. They know that the longer the boys remain inside, the smaller the window of opportunity to get them out safely.

NARONGSAK OSOTTHANAKORN CHIANG RAI GOVERNOR "Right now we try to pump the water out of the cave, and we try to do our best and tomorrow about 5 or 6 o'clock we will send the team inside and find the kids."

Q: And do you know how long you have?

A: I can't say how long but every minute is important.

Locals stop to offer prayers at a shrine close to the entrance. Many people here remain optimistic, but they're also aware that time is running out. Tony Cheng, CGTN, Tham Luang cave, Mae Sai, Northern Thailand.