Two Thais are now known to have died during the Hamas attacks on Israel on Saturday, the premier said after arriving in Hong Kong on Sunday afternoon.
Prime Minister Srettha Thavisin said he had received a report from Pannabha Chandraramya, Thai ambassador to Tel Aviv, that one more Thai national had perished in the conflict, raising the toll to two.
The ambassador said people of many nationalities had been kidnapped by Hamas militants, and battles were continuing along the border of the Gaza Strip. Israel had reoccupied only two areas, but neither contained workplaces for Thais, she said.
Foreign Affairs Minister Parnpree Bahiddha-Nukara said eight Thai people were injured and 11 Thais were captured.
Of the eight injured Thais, five were admitted to hospital and three others were awaiting rescue, the minister said.
Earlier on Sunday, Mr Srettha said a Thai worker was killed and about 11 others were captured during the Hamas attacks, while a total sky lockdown was delaying evacuations.
Before his overseas trip set from Sunday to Thursday, Mr Srettha said at Wing 6 in Don Muang there was an unconfirmed report that one Thai was killed and about 11 others were detained in Israel. He had not been informed of the exact number of injured Thai people there.
The prime minister said he would use all available diplomatic means to have the Thai victims freed. "They are innocent and have nothing to do with any conflict," he said.
There had yet to be a confirmed report on the whereabouts of the affected Thais, and people in Israel were ordered to stay home during ongoing lockdown measures, Mr Srettha said.
The air force was readying transport aircraft for the evacuation of Thai people from Israel where "the situation remains of concern," he said.
He advised the Thai ambassador in Israel to keep the aircraft on standby near Israel for quick evacuation when it is possible. However, the Israeli sky remained completely closed, he said.
One flight could carry 423 people, the prime minister said. There were about 25,000 Thai workers in Israel and about 5,000 of them were in locked-down areas.
Mr Srettha excluded Deputy Foreign Minister Jakkapong Sangmanee from his trip delegation and ordered him to remain in the country to oversee operations concerning the situation in Israel.
During this trip Mr Srettha will visit Hong Kong, Brunei, Malaysia and Singapore.