Thailand says 14 people including one soldier have been killed after several flashpoints along the disputed border.
At least 46 were injured.
Tensions have been running high since May.
The UK FCDO advice is to avoid all but essential travel to within the Thai-Cambodia border on both sides.
Thailand has closed land crossings along the entire 800 km stretch of border.
“Casualties have been reported, as well as evacuations of areas close to the border. Land borders/crossings between Thailand and Cambodia have been suspended, the Foreign Office said.
“Some tourist destinations in border areas such as the Khao Phra Wihan/Preah Vihear temple, the Ta Kwai/Ta Krabey temple and the Ta Muen Thom/Tamone Thom temple are currently closed.”
“There are also unexploded landmines in the border
