Among the Cabinet ministers, who took oath, were senior Congress leaders Vidya Stokes, Kaul Singh Thakur and G S Bali, who are considered Singh's detractors, while Sujan Singh Pathania, Thakur Singh Bharmauri, Mukesh Agnihotri, Sudhir Sharma, Prakash Chowdhary and Dhani Ram Shandil are from the Chief Minister's camp.
Thakur and Bali are stated to be confidants of Union Minister Anand Sharma, who is another power centre in the Himachal politics and is considered close to the central leadership of Congress.
A journalist-turned politician, Mukesh Agnihotri had been a functionary of Youth Congress while Sudhir Sharma had been active during the visits of Rahul Gandhi to the state.
Congress, which wrested power from BJP, has 36 MLAs in the 68-member Assembly and one independent MLA has extended unconditional support to the party.
With ten ministers including the 78-year-old Chief Minister taking oath, there are two more vacancies in the state Cabinet.
Singh, who has held the top office in Himachal five times in the past, was administered the oath of office and secrecy by Governor Urmilla Singh at an open ceremony at the historic Ridge Maidan here.
A large crowd had turned up for the function which was held outside the Raj Bhawan for the third time in the history of the state.
The new Council of Ministers has three members from Kangra from where Congress won ten out of fifteen seats, two from Shimla district, two from Mandi and one each from Chamba, Una and Solan districts. (More)
