KANSAS CITY, Mo. -- A man was shot by a liquor store security guard on Tuesday night, police said.

Officers said the guard told them a man, who he thought had a gun, was causing problems at the Royal Liquor Store on Southwest Boulevard about 9 p.m.

After telling the man to leave, the guard said the man became violent and during a struggle, the security guard shot him.

The man ran off, and police later found him in an alley about a block away. They did not find a gun.

The man's injuries are considered life-threatening, police said.