A plane, fishermen and and jet-skiers have joined an expanded search entering a third day for three Europeans, including two teenagers, who disappeared while diving off a southern Malaysian island.

Authorities were hopeful of finding them after Norwegian diving instructor Kristine Grodem was rescued on Thursday. She said the four of them surfaced safely on Wednesday afternoon but later drifted away from the boat and were separated by a strong current.

The group was diving about 50ft deep at an island off the town of Mersing in southern Johor state.

Ms Grodem, 35, was rescued by a tugboat about 22 nautical miles from the dive site.

The missing divers are Alexia Alexandra Molina, 18, from France, Briton Adrian Peter Chesters, 46, and his Dutch son Nathen Renze Chesters, 14.

Authorities deployed a Bombardier jet that can fly for longer and cover more area in an expanded search, said First Admiral Nurul Hizam Zakaria, Johor director of the Malaysian Maritime Enforcement Agency.

The plane was in addition to three helicopters, 11 boats and 100 personnel including rescue divers.

Adm Zakaria said members of the public have also lent support, with fishermen and 10 jet-skis helping to comb the sea. The weather was reported to be fair.

“It’s been three days since they went missing but we will not give up. We hope all of them will be rescued,” he said.

The search was halted on Friday night, and will resume early on Saturday.

Maritime officials said Ms Grodem was training the other three, who were seeking to obtain advanced diving licences.

The family of Ms Molina, who lives in Johor, sought support from private boat owners to join the search.

Esther Molina, 57, said she was optimistic that her daughter was still alive, adding: “My daughter is strong, she is smart. So now, we can only wait for developments.”

She said her daughter is due to attend a fashion college in Kuala Lumpur next month.

The boat skipper was detained for further investigation, and diving activities off Mersing have been suspended. There are several islands off the town that are popular dive spots for local residents and tourists.

Malaysia’s borders reopened to foreigners on April 1 after being closed for more than two years during the Covid-19 pandemic.