In a tweet, Modi also assured the JD(U) leader of all possible support from the Centre for the state's welfare.

"Congratulations to Nitish Kumar Ji on taking oath as Bihar's CM. I also congratulate all those who took oath as Ministers in the Bihar Government. The NDA family will work together for the progress of Bihar. I assure all possible support from the Centre for the welfare of Bihar," he said.

Kumar was on Monday sworn in as chief minister of Bihar for the seventh time in two decades at a ceremony in Patna which was attended by senior leaders including  Union Home minister Amit Shah and BJP national president Jagat Prakash Nadda.