The China National Tourism Administration issued advice on its website on Tuesday to urge mainland travelers to behave politely.

The advice asks tourists not to write on, or deface, relics, to refrain from spitting and not to talk loudly in public.

The advice was issued after a teenager from Nanjing, Jiangsu province, vandalized a stone sculpture in Egypt and triggered public outrage across the country.

A netizen wrote on Weibo on Friday that a Chinese tourist wrote “Ding Jinhao was here” at the 3,500-year-old Luxor Temple. The post was commented on more than 270,000 times, with most netizens critical.

Netizens later found it was written by a 15-year-old boy from Nanjing during a previous tour with his parents. The exact date it was written is still unclear.

The boy’s parents apologized on Sunday, saying that the boy cried all night over what he had done.

The writing was removed on Sunday and the Chinese Embassy in Egypt said that the result of further investigations will be released.