India's ruling Bharatiya Janta Party (BJP) on Saturday consolidated its position in the country's northeast after a landslide election victory in Tripura, ending 25 years of communist rule in the state.

Prime Minister Narendra Modi's BJP and its allies are also ahead in the mountainous state of Nagaland, while opposition Congress-ruled Meghalaya is heading for a fractured verdict.

Elections were held only in the states of Tripura, Nagaland and Meghalaya, where about nine million Indians live, according to the 2011 census. The three states have about 5.6 million voters, according to the election commission's website.

With Saturday's victory, the BJP-led National Democratic Alliance (NDA) will gain control over five of the seven northeastern states reshaping the political landscape of the region bordering Myanmar, Bhutan, Nepal and Bangladesh.

Modi, who had extensively campaigned in the three states, attributed the win to the development work by his party and its allies.

‘Time and again, election after election, the people of India are reposing their faith in the positive and development oriented agenda of the NDA,’ Modi tweeted.

The NDA already controls Assam, Manipur and Arunachal Pradesh. Congress-ruled Mizoram will vote later this year.

Congress leader Kamal Nath told reporters that his party is hopeful of forming the government in Meghalaya with support from other parties.

With control of Tripura and Nagaland, the right-wing BJP and its allies rule 21 of India's 29 states, boosting its prospects for a win in the federal elections scheduled for 2019.

India's main opposition Congress party, which has ruled the country for most of the time since independence in 1947, is now reduced to ruling three states.

The southern state of Karnataka, one of the bigger states ruled by the Congress, goes to the polls later this year.

‘Victory after victory is a positive sign. This has boosted our confidence even more for 2019,’ BJP president Amit Shah said.