President Donald Trump has pardoned two Oregon cattle ranchers whose sentence for arson led armed militiamen to seize control of a wildlife refuge in 2016.

Dwight Hammond, 76, and his son Steven Hammond, 49, were convicted in 2012 after a prescribed burn on their land spread to nearby public lands in 2001.

The pair served time in jail, but a judge later ruled that they must serve their full five-year sentence.

The ruling sparked anti-government protests that left one rancher dead.

"The Hammonds are devoted family men, respected contributors to their local community and have widespread support from their neighbours, local law enforcement and farmers and ranchers across the West," the White House said in statement on Tuesday announcing their full pardon.

"Justice is overdue for Dwight and Steven Hammond, both of whom are entirely deserving of these Grants of Executive Clemency.''

The Hammonds had claimed that the fire was to fend off invasive species, but prosecutors alleged that it was set to cover up evidence of illegal deer poaching and that it posed a grave risk to firefighters.

A judge had granted them a shortened jail stint, but in 2015 a federal judge ruled that they must complete their full sentences and sent them back to jail.

The case had drawn the attention of limited-government proponents, including the family of Nevada rancher Cliven Bundy who was himself facing charges relating to an armed standoff with law enforcement stemming from a refusal to pay fees for grazing on public lands.

His son, Ammon Bundy, then began a social media campaign backing the Hammonds, and travelled to Burns, Oregon, to organise protests calling for their release.

Mr Bundy and his group, Citizens for Constitutional Freedom, attracted supporters from across a number of states.

On 2 January 2016 the armed militiamen - who were never directly endorsed by the Hammonds - took over the Malheur National Wildlife Refuge and widened the range of demands.

The standoff ended when police arrested several members and fatally shot the group's spokesman, LaVoy Finicum, who they said was reaching for his gun during a traffic stop.

Susie Hammond, Dwight's wife and Steven's mother, told the Oregonian that she was asleep when her local congressman called to say that Mr Trump had signed the pardon.

"We've been waiting a long time. I think it's wonderful," she said, adding: "I still can't believe it. I won't believe it until I see them."

Last month she told the paper that she had "faith" in Mr Trump, adding: "If anyone is going to help them, he'd be the one."

Tuesday's announcement marks seven pardons by Mr Trump, as well as two commuted sentences.

Last month, Mr Trump granted clemency to 63-year-old Alice Johnson after meeting with celebrity Kim Kardashian, who lobbied the president for her release.