Two men died and four others were seriously injured Friday as a suspected case of arson struck a noodle restaurant in Odawara, Kanagawa Prefecture, police officials said.

Police on Saturday conducted investigation at the "soba" (buckwheat noodle) eatery.

A 53-year-old man who owns the land for the restaurant told an ambulance worker that the restaurant's 71-year-old manager poured oil on his head and started the blaze shortly after 1 p.m., the officials said.

There was apparently some trouble within the restaurant before the fire broke out. The landowner demanded the restaurant manager close the soba shop and vacate the property, they said.

The manager and another man are unaccounted for and are believed to be the two who died, the police said.

An explosion was heard and black smoke was seen billowing from the restaurant before firefighters managed to extinguish the fire about an hour later, police and firefighters said.

The four injured men, including the landowner, range in age from 23 to 66 and are all in the real estate business, police and firefighters said.

The restaurant was temporarily closed at the time of the incident, and the six men were inside, they said.

"All of a sudden I heard an explosion and saw a column of black smoke coming out of the restaurant," a local resident said Friday. "Then a man ran outside yelling."