Riot police in China's enclave of Macau have been called in to calm mainland tourists angry they were being shown too many shops and not enough sites.
Tourists wanted to see more sites like the St Paul's facade
More than 20 police armed with riot shields and batons were involved in a five-hour stand-off with 100 tourists from Hubei province, local media say.
The last straw came at a windy beach where the tourists were not allowed to retrieve warm clothing from coaches.
The gambling hotspot has become a key destination for mainland tourists.
The tourists had complained to their guides that they wanted to see more of the former Portuguese colony's historic sites.
They said they were being pressured into buying goods.
A scuffle broke out at the beach when the tourists were not allowed to re-board their four locked coaches to get some warmer clothing.
Police tried to push back the angry tourists with batons and detained at least four.
"Some tourists refused to let some of our colleagues go and attempted to use violence," one police officer told the South China Morning Post.
It was not until about 2200 local time (1400 GMT) that government officials persuaded the tourists to return to their hotels.
Macau tourism officials said the incident was a "one-off situation".
Tourist figures show that some 22 million people visited Macau last year, most from the mainland.
Also last year Macau was reported to have overtaken the famous Las Vegas Strip as the world's top gambling destination.