At least 12 Indian soldiers and a civilian were killed and 28 others injured when a four-storey building collapsed following heavy rains in Himachal Pradesh's Solan district on Sunday evening, the country's officials said today.

The bodies of deceased have been extricated so far from the debris, Solan Sub Divisional Magistrate Rohit Rathore said adding at least one person was still feared trapped under the debris, reports our New Delhi correspondent.

The actual number of those trapped inside would be clear only after the rescue operation ends by this evening.

The building, which housed a restaurant, collapsed on the Nahan-Kumarhatti Road on Sunday evening following heavy rains, officials said.

Himachal Pradesh Chief Minister Jai Ram Thakur, who visited the spot on Monday morning, said initial investigation has found that the structure was not built up to specifications.

"A magisterial inquiry has already been ordered. Strict legal action will be taken against erring persons after getting the report," he said adding a first information report (FIR) has been registered against the owner of the building.

An injured soldier told reporters from the hospital that when the building collapsed, there were 35 army personnel inside it, of whom 30 were Junior Commissioned Officers (JCOs).