Deputy Commissioner K.C. Chaman told IANS that 30 soldiers and 12 civilians were trapped in the debris and rescued after an over 22 hour operation by the National Disaster Response Force (NDRF), the Army and the state police.

The 28 people who were rescued comprised 17 soldiers and 11 civilians. The dead also included the building owner's wife.

Chief Minister Jai Ram Thakur, along with Minister Rajiv Saizal, MP Suresh Kashyap and Assembly Speaker Rajiv Bindal, visited the spot and also met the rescued people.

Thakur, who ordered a magisterial probe into the incident, said as per his information, the structure was not built as per construction specifications.

He ordered the registration of an FIR against building owner Shail Kumar, who was away along with his two children, when the structure collapsed.

According to officials, the incident took place at around 4 p.m. on Sunday when soldiers, belonging to the 4th Battalion of Assam Rifles from nearby Dagshai Cantonment, were having a party at the roadside eatery-cum-residential complex which caved in due to weak foundation.

The building was located on the Kumarhatti-Nahan road, around 55 km from Shimla.

The Deputy Commissioner said first, the fourth floor of the building collapsed and then the entire building caved in.

Three companies of the NDRF were involved in the rescue operation. The state deployed the Chief Minister's helicopter to airlift an NDRF team with its equipment from Sunni in Shimla district.

Locals blamed unscientific construction methods and violations in the granting of construction-sanction for the building collapse.