OSAKA -- A masked man with a knife robbed a small post office Tuesday morning in Osaka's Joto Ward, making off with around 20 million yen in cash, police said.

The man pulled a knife on the postmaster, 43-year-old Mitsuo Kubo, outside the post office at around 8:20 a.m. after Kubo had turned off the security alarms and unlocked the side entrance, investigators said.

Kubo handed him about 2 million yen from the office safe, but the man demanded more and made the postmaster take out another 18 million yen.