TOKYO: Thailand’s biggest foreign investor, Japan, said on Friday that it would offer support to its firms in the kingdom as concerns grow that the death of its revered monarch could derail the economy. Japan has more than 4,000 companies operating in Thailand, dubbed the “Detroit of Southeast Asia” due to the huge number of auto manufacturing plants. “The government will offer appropriate support to Japanese companies if necessary so that the impact on them would be kept to a minimum,” top Japanese government spokesman Yoshihide Suga told a regular press briefing. He did not elaborate on what sort of help — financial or otherwise — Tokyo might give. Concerns over the future of the country have been lingering with the ailing health of the world’s longest-reigning monarch, who has played a role of mediator at times of political turmoil during his seven-decade reign. King Bhumibol Adulyadej passed away Thursday at the age of 88 after years of ill health. “Significant near-term disruption is likely,” John Marrett, research analyst at the Economist Intelligence Unit, said in a commentary.