Two Central Industrial Security Force constables were on Wednesday night involved in a shootout that left one of them dead and the other seriously injured.

The incident took place outside the Purana Qila Road house of Delhi high court judge O P Dwivedi where the two constables were on duty.

There were, however, conflicting reports about the shootout.

While Delhi Police sources said constable Suresh Kumar shot at constable Kartar San after an altercation over duty hours, CISF Inspector General of Police Shafi Alam said Kumar first fired on San, ran some distance before turning the gun on himself.

Alam said there was no altercation between the two constables. One of the constables had approached a havildar for a pass to go out and the havildar had in turn told him to apply to an officer for the same, he added.

He said Suresh first fired in the air, then at the other constable before shooting himself.

Alam said stress was the factor behind the shoot-out. "Definitely, it is stress and we are working out how to reduce the stress," he added.

He said mental tension had resulted in the incident as 'had the mental balance been there, such incident would not have taken place'.

Both were rushed to the Ram Manohar Lohia hospital where Kumar was declared brought dead. San underwent an operation.