A 55-year-old man attacked four of his colleagues with a knife at the Karigari Bhavan in New Town on Thursday after the authorities allegedly declined his leave plea, police said.

The Karigari Bhavan is the headquarters of the technical education, training and skill development department of the state government.

It is located in Sector III of New Town.

The man, identified as Amit Kumar Sarkar, worked with the technical education department, the police said.

According to the police, around noon some bystanders alerted them about a man walking down the street holding a blood-stained knife.

A few pedestrians who tried to stop the man were asked to stay away.

A team of officers overpowered Sarkar and snatched the knife.

He was later arrested.

The four who were injured in the attack have been admitted to hospital.

Doctors told police that two of the injured were in a critical state.

"The man hails from Ghola in Sodepur. He claimed that his bosses denied him the leave that he wanted to take care of his ailing mother. He claimed that he carried the knife for his protection," said a senior officer of the Technocity police station under Bidhannagar police commissionerate.

Senior police officers said they were busy manning the Bengal Global Business Summit venue, about 7km from the spot of the incident, when the information reached them.

"We will question Sarkar to understand if he is in some mental distress. His statements about being denied leave have been recorded. We will cross-check it with his superiors," the police officer said.

Sarkar has also claimed that he has not received his salary for the last few months and alleged that some of his colleagues at the department had held back medical bills for his mother's treatment, the police said.