Brazil's education minister resigned Monday after coming under investigation over allegations he inappropriately channeled federal funds to political allies of two influential Evangelical pastors at President Jair Bolsonaro's request.

The ex-minister, Milton Ribeiro, had been in the hot seat since last week, when newspaper Folha de Sao Paulo revealed an audio recording of him saying he gave priority in deciding school-funding requests to municipalities governed by "friends" of the two pastors, at the far-right president's request.

"I have decided to ask the president to relieve me of my post, in order to ensure no doubt hangs over my conduct or that of the federal government," Ribeiro wrote in his resignation letter, published in the Brazilian media.

He denied wrongdoing, saying he was "fully convinced" his name would be cleared.

Bolsonaro accepted the resignation, according to a note in the government gazette.

Keeping Ribeiro had become "untenable," an administration source told AFP, speaking on condition of anonymity.

According to Folha, Ribeiro said at a meeting attended by Evangelical pastors Gilmar Santos and Arilton Moura that he prioritized funding requests from "friends of Pastor Gilmar," which he said was a "special request" from Bolsonaro.

One mayor said he had been asked for a kilo of gold in exchange for having his school-funding request cleared, reported newspaper Estado de Sao Paulo.

That triggered calls from opposition lawmakers for not just Ribeiro but the president to be investigated on charges of influence-peddling.

Bolsonaro, a conservative Catholic, won the presidency in 2018 with solid backing from Brazil's powerful Evangelical Christian movement.

He is keen to keep the Evangelical vote as he gears up to seek reelection in October, trailing in the polls to leftist ex-president Luiz Inacio Lula da Silva.