R. Kelly says his life is in immediate danger behind prison walls, and his legal team has filed an emergency motion seeking his immediate release!!!

According to court docs, obtained by TMZ, the Pied Piper’s attorneys claim they have evidence that outlines a murder-for-hire plot involving prison officials and another inmate to have him whacked inside the North Carolina penitentiary where he’s serving his 30-year sentence for sex crimes.

Kelly’s legal team submitted a sworn statement from a terminally ill inmate and Aryan Brotherhood gang leader named Mikeal Glenn Stine, who explicitly claimed authorities offered him his freedom to spend his last days on the outside — in exchange for murdering the singer.

The alleged plot was supposed to play out with Stine killing Kelly and getting charged for the deed, only for the prison officials to fumble the evidence and ultimately bury the case. Stine claims an official said he could be transferred after the deed and he’d be allowed to escape, and stay free.

Stine seemed like he was ready to carry out the murder … approaching R. Kelly’s housing area in March, only to turn back at the last minute and blow the whistle that Bureau of Prisons officials had ordered the hit. Stine approached Kelly personally in prison to inform him, according to the court docs. Stine’s indicated he’ll take a polygraph test and will offer to testify.

Kelly’s counsel says the flip was a costly one … now another member of the Aryan Brotherhood has been instructed to kill both Kelly and Stine — and the prison is crawling with more affiliates waiting in the wings.

We also obtained separate court docs Kellz filed with the U.S. Supreme Court asking them to review the case.