Nationalist Democratic Progressive Party leader Neiphiu Rio took oath as the chief minister of Nagaland for the fifth term.
The 72-year-old politician was administered the oath of secrecy by Governor La Ganesan.
T R Zeliang and Y Patton were sworn-in as the deputy chief ministers of the state, while other members of the Rio cabinet also took oath.
State BJP chief Temjen Imna Along, widely popular on social media across the country for his sense of humour, and Salhoutuonuo Kruse, one of the two women elected to Nagaland assembly for the first time, were among those who were sworn-in as members of the council of ministers.
Prime Minister Narendra Modi, Union Home Minister Amit Shah, BJP president J P Nadda and Assam Chief Minister and NEDA convenor Himanta Biswa Sarma were among those present on the occasion.
Rio will lead an all-party opposition less government, even as the NDPP-BJP alliance secured 37 seats in the 60-member House in the recent assembly polls in the northeastern state.
All other parties in the state have extended their letters of support to the Rio-led alliance.