Guwahati, May 24 (IANS) 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.