The four accused arrested in connection with the rape and murder of a woman veterinarian near Hyderabad last month were killed in an alleged encounter with the police on Friday morning, police said.

'The four accused were killed in an encounter with the police,' Cyberabad police commissioner V. C. Sajjanar said.

The Telangana police said its personnel resorted to 'retaliatory' firing after two of the accused in the rape and murder case opened fire at them after snatching weapons from them.

The police returned fire after initial 'restraint' and asking the accused to surrender, he told reporters.

The snatched weapons were in 'unlocked' position, he added.

The accused were not handcuffed when the firing took place and the incident happened between 5.45am and 6.15am this morning, he said.

Detailing the events leading to the exchange of fire, the top official said the police team brought the accused to the location based on their 'confession' to recover a cellphone and 'other objects.'

'...all the four accused got together, they started attacking the police party with stones, sticks, and other material. And they also they snatched away weapons from our two officers and started firing,' he said.

'Even though our officers maintained restraint and asked them to surrender, without listening to us, they continued to fire and attack...our people retaliated,' Sajjanar said.

'And in that retaliation four accused got killed,' he said.

The injured, a police sub-inspector and a constable, had suffered head injuries among others and were undergoing treatment, he said.

The police were collecting data from other parts of the state, besides Andhra Pradesh and Karnataka on similar cases to ascertain if the four had any role in them, Sajjanar added.

The four men, all lorry workers, aged between 20 and 24, were arrested on November 29 for allegedly raping and killing the woman by smothering her and later burning her body.

They were in remanded to 7 days' judicial custody.

The gang rape and murder triggered a nationwide outrage with the public and lawmakers demanding speedy punishment to the perpetrators.

The state government had ordered setting up of a fast track court to expedite the trial.