Donald Trump was wrong to pardon Joe Arpaio, says Congress's highest-ranking Republican Paul Ryan

Paul Ryan, the highest-ranking Republican in Congress, has condemned Donald Trump's decision to pardon of controversial former sheriff Joe Arpaio.

The party's speaker in the House of Representatives said he "does not agree" with the decision, joining other senior Republicans in a chorus of criticism.

Mr Arpaio, 85, was convicted of criminal contempt in July last year after ignoring a court injunction ordering him to stop racially profiling Latinos in Arizona.

The former sheriff of Maricopa County had faced possible jail time over his department's policy of detaining motorists on suspicion of being illegal immigrants based solely on their race.

The political ally of Mr Trump was granted the first pardon of the billionaire's administration this week in a move described by critics as "a presidential endorsement of racism".

"The speaker does not agree with this decision," a spokesman for Mr Ryan said. "Law enforcement officials have a special responsibility to respect the rights of everyone in the United States. We should not allow anyone to believe that responsibility is diminished by this pardon."

John McCain, the veteran Arizona senator and former Republican presidential candidate, led the criticism of Mr Trump over the pardon, which he said “undermines his claim for the respect of rule of law".

The President has repeatedly praised Mr Arpaio's hardline stance on immigration, which included huge round-ups of suspected illegal migrants.

The former sheriff, who lost a bid for re-election in November after 24 years in office, was also notorious for his investigation into unfounded Trump-promoted claims questioning former president Barack Obama's US citizenship.

"Throughout his time as sheriff, Arpaio continued his life's work of protecting the public from the scourges of crime and illegal immigration," said a White House statement announcing the pardon.

In July last year US District Judge Susan Bolton ruled Mr Arpaio he had willfully violated a 2011 injunction barring his officers from stopping and detaining Latino motorists solely on suspicion that they were in the country illegally.

The self-proclaimed "toughest sheriff in America" claimed the prosecution was a politically motivated attempt by the Obama administration to undermine his re-election bid. Mr Trump said Mr Arpaio had been convicted "for doing his job".

He had been due to be sentenced on October 5 and faced a fine and maximum sentence of six months in jail.

Cecillia Wang, a lawyer who helped press the racial profiling case, described the pardon as ”a presidential endorsement of racism”.

She said Mr Trump had "acted in support of illegal, failed immigration enforcement practices that target people of colour and have been struck down by the courts".