The families of Thai labourers held hostage by Hamas spoke Tuesday of their fears for their safety, after the Palestinian militant group threatened to kill civilian captives in its war with Israel.

At least 18 Thais have been killed and 11 seized since Hamas launched a surprise attack on Israel on Saturday.

Hamas dragged off around 150 people as hostages in its attack, and has said it will kill them one by one if Israel continues to hit Gaza with air strikes.

Kanyarat Suriyasri, whose husband Owat Suriyasri is among those taken, spoke of her horror at learning the news.

"When I heard that he was among the 11 hostages taken by Hamas my heart dropped," she told AFP.

"I am waiting to hear some good news."

Owat, 40, from Si Saket province in eastern Thailand, is a "very friendly, caring and happy man", she said.

He moved to Israel in 2021 for improved wages, hoping to build a better house for his wife and two children.

"We have a lot of debts, and working abroad pays better than in Thailand," she said.

She told AFP that if she could see her husband she would tell him: "I've missed you, I won't let you go anywhere far away again.

"I would hug him."

- 'I hope he survives' -

Wannida Ma-asa's husband Anucha Angkaew, an avocado farm worker, was another of those taken hostage.

"I'm devastated. I spoke with him the day when he was kidnapped. I had a video call with him before it happened and we chatted normally," she told AFP.

But despite Hamas's threat to kill its captives, Wannida said she was holding out for the safe return of her husband, who is 28.

"I really hope he survives... I have a 100 percent hope. I am patiently watching the news, waiting to hear some good news," she said.

Anucha, who has a daughter, moved to Israel in March 2022 from his home region of Udon Thani, an agricultural area in northeast Thailand.

There are around 30,000 Thais working in Israel, many in the agricultural sector.

Many are labourers from Thailand's poor rural northeast seeking to benefit from higher wages to build up a nest egg and improve the lives of their families back home.

They have been vulnerable to exploitation. A 2015 Human Rights Watch report found that migrant workers had been housed in inadequate accommodation and paid less than the legal minimum wage.

- Waiting for help -

Many Thai families are enduring a painful wait for news of missing relatives.

Jittawan Promsudorn said her family had lost contact with her cousin Adisak Pengsuwan, who had been working on a farm in the Gaza Strip area since March 2022.

They have heard nothing from him since the early hours of Tuesday morning, she said.

"Earlier he told us that all of his friends were all shot dead, but he was lucky to be able to run away to a bunker," she told AFP.

"He was stuck in a bunker with 19 other Thais, but there was no food or drinkable water. He told us that he wanted to go out to get some food and water but was afraid for his life."

Adisak was waiting for help from Thai officials, she said.

"Our family, especially his mother is now distressed and she checks in with me every hour if I have heard back from her son," she said.

The Thai foreign ministry said that 5,000 of its nationals have been moved away from high-risk areas to safety.

More than 3,000 Thais have asked to be repatriated and a first flight will leave Israel on Wednesday, carrying those who are injured but fit to travel, the ministry said.