TERRE HAUTE, Ind. (NewsNation) — The only Native American on federal death row was put to death Wednesday, despite objections from many Navajo leaders who had urged President Donald Trump to halt the execution on the grounds it would violate tribal culture and sovereignty.

With the execution of Lezmond Mitchell for the grisly slayings of a 9-year-old and her grandmother, the federal government has now carried out more executions in 2020 than it had in the previous 56 years combined.

Mitchell, 38, and an accomplice were convicted of killing Tiffany Lee and 63-year-old Alyce Slim, who had offered them a lift in her pickup truck as they hitchhiked on the Navajo Nation in northeastern Arizona in 2001. They stabbed Slim 33 times, slit Tiffany’s throat and stoned her to death. They later mutilated both bodies.

Mitchell expressed no remorse during the public portion of the execution. Asked by a prison official if he had any last words for victims’ family members and other witnesses behind glass at the death chamber, Mitchell casually responded, “No, I’m good.”

Moments later, prison officials began the lethal injection of pentobarbital that flowed to IVs in his hands and forearms in the tiny, pale-green death chamber at the federal prison in Terre Haute, Indiana.

Mitchell lay strapped down on his back, his glasses still on and a medical mask across his face, never moving or tilting his head to look around the room. His chest heaved and his thumb tapped the gurney momentarily, as his breathing became labored and his stomach area began to throb. But after about 10 minutes, Mitchell no longer appeared to move at all and his partially tattooed hands turned pale.

An official with a stethoscope checked for a pulse and listened to Mitchell’s hear before he was declared dead at 6:29 p.m. EDT. It took nearly 30 minutes for him to die.

Mitchell had long maintained that his accomplice, Johnny Orsinger, took the lead in the killings. Orsinger was a juvenile then and couldn’t be sentenced to death. He’s serving a life sentence in Atlanta.

The Navajo government asked Trump to commute Mitchell’s sentence on grounds his execution would violate Navajo culture and sovereignty. A federal judge in Washington, D.C., denied an attempt by Mitchell’s lawyers for a last-minute court intervention. There was no immediate word on whether they would appeal the ruling to the circuit court, and ultimately the U.S. Supreme Court, which declined late Tuesday to step in and halt the execution.

Under President Trump, the Justice Department resumed executions this year after a 17-year hiatus, killing three condemned men in July at the federal prison in Terre Haute, Indiana.

Last month, the department scheduled Mitchell’s execution for Aug. 26, angering some Navajo officials.

“It’s a complete slap in the face to our values and our justice system and the deference that’s owed to us as guest of ours on this land,” Carl Slater, a member of the Navajo Nation Council who represents Mitchell’s home district, said in an interview.

Under the Major Crimes Act, the federal government has jurisdiction over certain major crimes occurring on American Indian territory, including murder but usually cannot pursue capital punishment for a Native American for a crime on tribal land without the tribe’s consent.

Navajo officials, along with other leaders of other tribes, have opposed the death penalty, including in Mitchell’s case. But John Ashcroft, attorney general under then-President George W. Bush, overrode federal prosecutors in Arizona who said they would defer to the tribe’s position against pursuing a capital case.

In what Mitchell’s lawyers deride as a legal loophole, federal prosecutors successfully pursued a capital case against Mitchell for carjacking, a capital crime that is not among those listed in the Major Crimes Act.

Prior to this year, the federal government had carried out just three executions since 1963, all of them between 2001 and 2003, according to the Washington, D.C.-based Death Penalty Information Center. Oklahoma City bomber Timothy McVeigh was among them.

The first of the resumed executions was of former white supremacist Daniel Lewis Lee on July 14. Two others, Wesley Purkey and Dustin Honken, were executed later the same week. The victims of all three also included children.

Keith Nelson, who was also convicted of killing a child, is slated to die Friday at the Terre Haute, Indiana, prison where all federal executions are carried out by a lethal injection of pentobarbital. Nelson’s lawyers say pentobarbital can cause severe pain and so should be deemed unconstitutional.

There are currently 58 men and one woman on federal death row, many of whose executions have been pending for over 20 years.

The executions of Christopher Andre Vialva and William Emmett LeCroy are scheduled for late September.