FILE - This Jan. 26, 2016, file photo taken from an FBI video shows Robert "LaVoy" Finicum, center, after he was fatally shot by police near Burns, Ore. A federal judge declined to dismiss any charges Monday, Feb. 26, 2018, against FBI Special Agent W. Joseph Astarita, who is accused of lying about firing two shots at Finicum in the takeover of a national wildlife refuge in Oregon. (FBI via AP, file)

PORTLAND, Ore. - A military veteran described as the architect of the armed takeover of a national wildlife refuge was sentenced Tuesday to three years and a month in prison, the longest sentence for anyone convicted in the case.

At the federal courthouse in Portland, Ryan Payne of Anaconda, Montana, apologized to those disrupted by his actions and to the American people in general. He also promised to sever ties with militia groups.

Payne, 34, helped seize the bird sanctuary in southeastern Oregon on Jan. 2, 2016, in a protest against federal control of Western lands and the imprisonment of two ranchers convicted of setting fires. He and standoff leader Ammon Bundy had come to Oregon two months earlier, warning Harney County Sheriff Dave Ward of civil unrest unless he told the federal government that ranchers Dwight and Steven Hammond would not report to prison.

Federal prosecutors said Payne had a leadership role during the ensuing occupation. In charge of defence, he co-ordinated armed guards and provided tactical training.

Assistant U.S. Attorney Geoff Barrow sought a sentence of more than three years, telling U.S. District Judge Anna Brown that Payne was the "most culpable" of the nearly 20 defendants receiving sentences in the case. Ammon Bundy and six co-defendants were acquitted by a jury in October 2016.

"The patriot community at large needs to understand that an offence of this nature...is a serious offence that warrants a serious sentence," Barrow said.

Payne was arrested Jan. 26, 2016, during a traffic stop while travelling with Arizona rancher Robert "LaVoy" Finicum and others to a community meeting away from the refuge. Payne complied with officers and left the vehicle. Finicum and the others drove away, and Finicum was fatally shot by authorities at a roadblock.

He pleaded guilty to conspiracy in July 2016, and later unsuccessfully tried to withdraw his plea. The sentencing was pushed back until after the outcome of his trial on charges stemming from a standoff with federal agents at a Nevada ranch owned by Ammon Bundy's father, Cliven.

The judge in the Nevada case dismissed charges against Payne and the Bundys last month, citing federal prosecutors' misconduct with evidence.

Payne's lawyer, Lisa Hay, argued for a sentence of two years, which would essentially be a punishment of time served because Payne spent about that much time in Portland and Las Vegas jails awaiting trial.

Psychologist Suzanne Best testified for the defence Tuesday that Payne suffered post-traumatic stress disorder from his two tours of combat duty in Iraq. She said Payne has had a mental shift while in custody, and has become more willing to undergo treatment.

Payne, she said, now wants to focus on his family instead of militia activities and other activism.

But Judge Brown expressed skepticism that Payne is ready to stop associating with co-defendants and militia groups. She was particularly bothered that Payne violated his release conditions by visiting the Bundy ranch in Nevada in December without permission. Photos of Payne grinning appeared on social media.

"It was as if you were celebrating the win but in a way that once again thumbed your nose, I'll say politely, against the rule of law," Brown said.

News from © The Associated Press, 2018