Tragedy struck 48 passengers of an ill-fated Kerala transport bus at Tirupur in Tamil Nadu on Thursday, when the vehicle collided with a lorry head on, leaving at least 20 dead and many injured and was reduced to a heap of metal in the impact.

All the 20 were killed on the spot and six of the victims were women, police said. The crash happened at Avinashi town in Tirupur, 40 km from Coimbatore.

The mangled remains of the Kerala State Road Transport Corporation (KSRTC) bus gave a picture of the severe hit it took, after the container lorry entered the wrong lane and rammed into it.

The injured have been admitted to hospitals in Tirupur, while some have been referred to Coimbatore.

Most of deceased have been identified, Palakkad superintendent of police Siva Vikram told PTI.

'It was a high speed collision. The container lorry lost control. We do not know if the driver dozed off or the tyre burst.'

'The lorry entered the wrong lane and crashed into the KSRTC bus coming in the opposite direction,' he said adding 'We are taking the names and details.'

The bus was heading towards Thiruvananthapuram from Bengaluru, while the lorry was coming from the opposite direction on the Coimbatore-Salem Highway when the mishap occurred in the early hours of Thursday, police said.

Kerala chief minister Pinarayi Vijayan condoled the death of the victims and directed transport minister A. K. Saseendran and agriculture minister V. S. Sunilkumar to rush to Tamil Nadu to coordinate relief operations, the CMO said.

He also directed the Palakkad district collector to take necessary steps to provide medical aid to the injured and bring back the bodies of those hailing from Kerala, the chief minister's office said.

The CMO said it was in regular touch with Tirupur district administration and efforts were on to identify the bodies.

According to reports, most of the passengers were from Palakkad, Thrissur and Ernakulam districts of Kerala.

Passengers, including women, who had a narrow escape from the tragedy, were yet to recover from the fact that many of their fellow travellers had lost their lives.

Karishma, who was on her way to Ernakulam, said she was seated on the left side of the bus and was sleeping when the accident occurred.

'When I woke up suddenly, I saw many people running around and the injured being taken in ambulances,' the shocked woman told media.

Alan, also from Kerala, said he was still finding it difficult to overcome the shock.

'I have sustained a minor injury on my leg. But my friend is injured on the nose and I am taking him to hospital,' he said.

Jemin George, an injured passenger, said he suffered a cut on his lips and an injury on forehead that required 10 stitches.

'I didn't know what exactly happened. I was sleeping in a seat behind the driver's seat,' he said, adding, he was referred to a hospital in Coimbatore.

A weeping woman passenger said the container lorry was overloaded and there were not many vehicles on the road when the incident took place.

She said the right side of the bus was fully damaged.