In tweets after the bypoll results came, he said it was an "appreciable effort" by NDA.
"Happy to see the victory of BJP and allies in by-polls in northern, southern, eastern, western and central parts of the country. I express gratitude to the people," he tweeted.
"Appreciable effort by NDA. People across India reposed faith in politics of development, development & development. 'Sabka Saath, Sabka Vikas'," Modi added.
Appreciable effort by NDA. People across India reposed faith in politics of development, development & development. Sabka Saath, Sabka Vikas— Narendra Modi (@narendramodi) February 16, 2016
BJP wrested the communally-sensitive Muzaffarnagar constituency in Uttar Pradesh where the ruling Samajwadi Party suffered a blow losing two of the three seats it had while the Congress was jolted in Karnataka where it lost two of the three seats.
BJP ally RLSP won Harlakhi constituency in Bihar, defeating Congress nominee in the state where the RJD-JD(U)- Congress coalition came to power with a massive majority in the Assembly elections only three months ago.
In four other states -- Madhya Pradesh, Maharashtra, Punjab and Telangana -- ruling parties BJP, Shiv Sena, Akali Dal and TRS emerged victorious respectively in one seat each. In Tripura, again it was the ruling CPI (M) which won the lone seat.
The by-elections were held for 12 seats across eight states, results of which were declared today.