Ghaziabad, Jul 17 (IANS): The death toll in the collapse of a five-storey building under construction here rose to four Sunday, with two more people succumbing to their injuries, police said.

The disaster happened Saturday afternoon when the building tumbled down in Shalimar Garden area, trapping several workers.

Rescuers -- including residents, fire brigade, police personnel and soldiers -- worked frantically to rescue those tripped under tons of concrete, witnesses said.

The injured were rushed to hospitals, said Chief Medical Officer Ajay Agarwal. Some of the over dozen still warded in hospitals were said to be in serious condition.

Most of the workers were from West Bengal, Orissa, Madhya Pradesh, Jharkhand and Bihar.

Superintendent of Police City J.K. Sahi said soldiers were summoned from Meerut. The National Disaster Management and the Indian Air Force station at Hindon in the region were also helping, he said.

Five cranes were deployed to remove tonnes of concrete. Four people, including contractor Kishan Singh, have been arrested.

"The entire building has fallen," said Vinod, an eyewitness.

The building was being constructed over an 800 square metre plot. Three cars, parked in its vicinity, were destroyed.