BANGKOK (AP) — A Briton and Canadian face up to 10 years in prison on charges of spraying paint on an ancient wall in northern Thailand, police said Friday.

Security camera footage purportedly showed Furlong Lee and Canadian Brittney Lorretta Katherine Schneider, both 23, spraying a message on the walls of the Tha Pae Gate in the northern province of Chiang Mai at around 4 a.m. Thursday.

Pol Col. Teerasak Sriprasert, chief of the Chiang Mai police, said that the tourists are in custody and have been charged with vandalizing registered ancient artifacts, which carries a penalty of up to 10 years in prison and a million baht ($30,650) fine.

Teerasak said the pair admitted sprayed the message out of drunken revelry. He said that Lee, who is from Liverpool, admitted that he wrote "Scouser Lee" on the wall while Brittney told police that she wrote the letter "B'' underneath it.

The 13th century Tha Pae Gate is part of an ancient wall that forms a square around Chiang Mai's inner city.