The couple had previously been warned by police to stay away from each other following a dispute over their child.
An Iranian man set his Filipino girlfriend on fire following an argument in a restaurant in Japan, local media reported Saturday.
The incident which took place at an eatery in Ibaraki, North of Tokyo, is a rare case of violence in the country.
"People are burning," a worker at the restaurant said when calling for an ambulance.
The 52-year-old man was seen pouring liquid on the 36-year-old woman and then igniting it, causing both of them to catch on fire.
The couple was then taken to hospital with severe burns where they remain unconscious, public broadcaster NHK said.
There were other customers inside the restaurant at the time, however, no one else was injured.
The woman had consulted with law enforcement in October, when the man threatened to kill her if she prevented him from seeing their child, Japan Today cited police as saying.
Police are treating the case as an attempted murder.