The incident occurred at around 12.45 pm at Sainapalem village when the 40-year-old man identified as Seshaiah suddenly attacked the four with a axe lying on a road, they said.
The accused had recently underwent treatment at a hospital for "mental disorder", a police officer said adding he has been taken into custody and his further interrogation would only reveal the actual reason for the attack.
"Whether the attack was done intentionally or without any provocation will be known only after thorough inquiry," the police officer said.
Kandaleru police have registered a case of attempt to murder against the accused.