Ayatollah Ali Khamenei, Iran's supreme leader, has turned to Twitter to lambast U.S. authorities for their treatment of minorities, spotlighting Monday's anniversary of the 1890 massacre at Wounded Knee and tweeting #BlackLivesMatter in solidarity with protesters in New York and Missouri.

In a tweet posted Sunday, Khamenei referred to racial unrest in Ferguson, Mo., asserting: "#Jesus endured sufferings to oppose tyrants who had put humans in hell in this world & the hereafter while he backed the oppressed. #Ferguson."

He was referring to the fatal shooting of unarmed African American teenager Michael Brown on Aug. 9, which set off months of rioting against authorities in Ferguson and a national debate on law enforcement's relations with minorities.

Later in the day, the ayatollah added his voice to the campaign against racial profiling by police that accelerated with the Dec. 4 death of 43-year-old Eric Garner in New York. Garner had been put in a chokehold by officers who stopped him for selling bootleg cigarettes on the street.

"It's expected that followers of #Jesus follow him in his fight against arrogants and in his support for the oppressed. #BlackLivesMatter," Khamenei wrote, including the hashtag that has become a rallying cry since the Brown and Garner deaths.

Khamenei had also tweeted a similar message of support on Christmas Eve, likening U.S. minorities' plight with that of Palestinians in the Gaza Strip. "If #Jesus were among us today he wouldn't spare a second to fight the arrogants & support the oppressed. #Ferguson. #Gaza."

Khamenei added the treatment of Native Americans in the United States to his tweeted laments, noting Monday's 124th anniversary of the 7th Cavalry Regiment massacre of captured Lakota Sioux Indians at Wounded Knee Creek in South Dakota. As many as 300 Lakota men, women and children died in the attack, which became an evocative symbol of white repression and a focal point of Native American protests.

"Western culture is an aggressive one. Wherever Westerners went, they destroyed local culture, history & language. #NativeLivesMatter," Khamenei said in a series of tweets that included gruesome photos of dead Lakota awaiting burial in a mass grave.

The Iranian religious leader's embrace of Twitter to denigrate U.S. policy was more significant for its method than message, as Khamenei has been among the most anti-American voices in Iran since the 1979 Islamic Revolution overthrew U.S.-allied Shah Mohammad Reza Pahlavi.

Khamenei's Twitter profile shows he has 91,600 followers and follows only three other Twitter accounts: his own Arabic and Farsi streams and the statements and messages of late revolutionary leader Ayatollah Ruhollah Khomeini.

Khamenei's recent missives deviated in tone and content from Iranian President Hassan Rouhani's Christmas greetings on Twitter last week.

"May Jesus Christ, Prophet of love & peace, bless us all on this day. Wishing Merry #Christmas to those celebrating, esp Iranian Christians," Rouhani tweeted, in a missive radically different from Tehran's vitriolic rants of the previous 35 years.

Muslims consider Jesus a prophet, but do not accept that he was crucified or resurrected.

Rouhani spent more than two decades within the Islamic Republic's Supreme Council but was seen during his come-from-nowhere presidential campaign in early 2013 as a political figure offering a new relationship with the West after more than three decades of animosity.

Rouhani's perceived overtures, however, appear to have been countered by the more entrenched anti-American sentiments of the ruling clerics.