India's most populous state has stopped paying some 21,000 teachers of subjects including mathematics and science in Muslim religious schools, or madrasas, an official said on Thursday, and they could lose their jobs altogether.

The teachers work at madrasas in Uttar Pradesh, ruled by Prime Minister Narendra Modi's Hindu nationalist party, and the move comes ahead of Modi seeking his third straight term in a general election due by May.

"Over 21,000 teachers are set to lose their jobs," Iftikhar Ahmed Javed, chief of Uttar Pradesh's madrasa education board, told Reuters. "Muslim students and teachers will go back by 30 years."

Muslims are a minority in mainly Hindu India, accounting for about 14% of a population of 1.42 billion, and they make up nearly a fifth of the population of Uttar Pradesh.

Rights groups such as Human Rights Watch say nationalist groups have threatened and harassed Muslim and other religious minorities with impunity under Modi's Bharatiya Janata Party (BJP), accusations the party denies.

According to a document seen by Reuters, the federal government stopped funding the programme, called the Scheme For Providing Quality Education in Madrasas, in March 2022.

The document, from the Ministry of Minority Affairs, shows Modi's government did not approve any new proposals from states under the programme between the 2017/18 and 2020/21 fiscal years, before closing it altogether.

Modi's government raised funding for the programme to a record of about 3 billion rupees ($36 million) in the fiscal year to March 2016. His office did not respond to a request for comment.

India's minority affairs ministry, which ran the programme until it was closed, also did not respond to requests to comment.

The document did not cite a reason but a government official said it could be because a 2009 law ensuring free compulsory education for children covers regular government schools.

Government data shows more than 70,000 madrasas were covered in the first six years of the programme, started in 2009/10 by the previous government run by the Congress party.

The programme benefited Muslim children and should be revived, said Shahid Akhter, a member of a government panel on minority educational institutions.

"Even the prime minister wants children to have both Islamic and modern education," he told Reuters. "I am already talking to officials to see that the scheme is retained."

The federal government told states about ending the programme only in October last year, according to a letter Uttar Pradesh madrasa official Javed sent to Modi on Wednesday.

He said his state had not paid its share to the teachers since April and decided to stop paying altogether this month, while the federal portion had not been paid for six years.

But they "were doing their work smoothly in the hope your kindheartedness would resolve the issue," added the letter from Javed, who is also the national secretary the BJP Minority Front.

A senior Uttar Pradesh information official had no immediate comment.

The state used to pay up to 3,000 rupees ($36) a month from its own budget to the teachers of subjects including science, maths, social studies, Hindi and English, on top of up to 12,000 rupees from the federal government.

"We do not have any other job and I am too old to get another one," said Samiullah Khan, a madrasa teacher from Bahraich district for the past 14 years.

The northeastern state of Assam, meanwhile, is converting hundreds of madrasas into conventional schools, despite protests from the opposition and Muslim groups. Its chief minister has called for all states to stop funding madrasas.

Many madrasas in India are funded by donations from members of the Muslim community, while others rely on government aid.