Thailand officially started a year of mourning a day after revered King Bhumibol Adulyadej died at the age of 88. Thais will only wear dark colors and there will not be any public celebrations for at least a month.

The initial mourning period is likely to hit tourists in the country. Tourism Authority of Thailand said Friday that tourists can continue with their travel as planned and popular spots will remain open with exception of Wat Phra Kaew (Temple of the Emerald Buddha) and the Grand Palace in Bangkok due to the royal funeral rites.

However, the U.S. the U.K. and New Zealand have issued advisories to its citizens and urging them to be respectful during the time.

“Our thoughts and sympathies are with the members of the Royal Family and the people of Thailand at this somber time. We urge U.S. citizens visiting or residing in Thailand to join us in showing respect by maintaining decorum during this extended period of profound mourning,” U.S. Embassy & Consulate in Thailand said in a statement.

Similarly, U.K. asked its citizens to wear “respectful clothing” and behave in an appropriate manner in public.

“You should respect the feelings and sensitivities of the Thai people at this time. Particularly during the first 30 days of the mourning period, some entertainment venues, including restaurants, bars, and clubs may be closed or operating on restricted hours. You should wear dark-colored sombre and respectful clothing when in public and behave respectfully when in public areas. Check local media regularly and follow the advice of the local authorities,” the advisory read.

New Zealand warned its citizens in Thailand to expect delays at places due to short-staffing.

“New Zealanders travelling to, or residing in Thailand should expect limitations and restrictions to be placed on some activities and services at this time. There may be periods of delay due to reduced staff numbers, periods of closure, and the local observance of mourning periods. This may include travel delays, reduced access to financial services [possibly including ATMs], and the temporary closure of, or delays in the provision of other government services,” according to the travel advisory.

Chinese travel agencies are advising people against travelling to Thailand during the mourning period. China has not issued any advisory for its citizens in Thailand, but travel companies have started refunding bookings and have urged travelers to maintain decorum in Thailand, South China Morning Post reported.

Bhumibol, the world’s longest reigning monarch, died Thursday at the Siriraj Hospital in Bangkok. He had been put on ventilator and was battling a new infection.