Guwahati: Sarabananda Sonowal was on Tuesday sworn-in as the first BJP chief minister of Assam at a gala event here attended by Prime Minister Narendra Modi, his senior cabinet colleagues and tens of thousands of BJP supporters.

Sonowal, 53, took oath along with Himanta Biswa Sarma, the former Congress strongman who crossed over to the BJP last year and is largely credited for the BJP's massive electoral victory in the northeastern state.

The ceremony, also attended by BJP president Amit Shah, was held at the sprawling Khanapara rally ground in the city that was turned saffron with Bharatiya Janata Party (BJP) flags fluttering all over.

Also present at the event were the chief ministers of the BJP-ruled states and leaders of the National Democratic Alliance (NDA).

Former chief minister Tarun Gogoi, who ruled the state for 15 years before Sonowal dethroned him, also attended the ceremony.