New Delhi: RLSP leader Upendra Kushwaha on Monday quit the BJP-led NDA and the Modi government, charging Prime Minister Narendra Modi with betraying Bihar and with pursuing an "opaque style of functioning and non-democratic leadership style".

Kushwaha, who is the second BJP ally to quit the Modi government after the Telugu Desam Party (TDP), said in his resignation to Modi that the Union Cabinet "has been reduced to a mere rubber stamp".

"Constitutional offices are being undermined and virtually every institution in the government has been subjected to political appropriation," he said in the letter, echoing the charges increasingly made by the opposition.

"Ministers and officers posted in ministries have become figureheads as virtually all decisions are taken by you, your office and BJP President (which is anti-Constitutional)."

The Rashtriya Lok Samata Party leader said the government was pursuing "the agenda of RSS" which he said was "anti-Constitutional and neglecting and subverting the agenda of social justice enshrined in the Constitution for which we supported the NDA".

Kushwaha has been at loggerheads with both the Bharatiya Janata Party and the Janata Dal-United (JD-U) for some time. As meetings he had sought with Modi and BJP President Amit Shah did not materialize, he came for praise from RJD leader Tejashwi Yadav.

"Having served in your Council of Ministers for the last 55 months, I stand dejected and betrayed by your leadership," he said in the letter sent to Modi.

"There has been a fundamental conflict in what you have promised to the people before elections and what you have actually delivered after coming to power."

"The promise of providing a special package (to Bihar) has been the biggest 'jumla'," he said in the resignation letter.

"The fact of the matter is that under your leadership grave and unprecedented injustice has been committed upon the people of Bihar, I say with a sense of deep regret and sorrow."

He told the media that the government had been working to the agenda of the Rashtriya Swayamsewak Sangh (RSS) and that many with RSS background had been made Vice Chancellors across the country.

Asked if he would join an opposition alliance or merge his party with Sharad Yadav's Loktantrik Janata Dal or work for a third alternative in Bihar, he said: "All options are open for us. We would be taking a call in the coming days."