John Lewis, a towering figure of civil rights era, during a past address in 2017. [File]

President Uhuru Kenyatta on Sunday joined world leaders and activists in eulogising rights crusader John Robert Lewis – famed for standing up against racial injustices – who died on Friday.

The long-time US congressman died of pancreatic cancer barely six months after announcing late last year that he had been diagnosed with stage 4 of the disease. He was 80-years-old.

Uhuru described him as a "freedom icon, gifted orator and political maverick" and that his death had robbed the world an "inspirational politician whose achievements helped shape the careers of many renowned global leaders."

"President Uhuru wished God's comfort to the family of the Congressman, members of his Democratic Party and his supporters during this difficult period of grief," State House said in a statement.

Former US President Barack Obama, recalling his first interaction with Lewis when he was a law student, said those who met him were always struck by his gentleness and humility.

"He loved this country so much that he risked his life and his blood so that it might live up to its promise. And through the decades, he not only gave all of himself to the cause of freedom and justice, but inspired generations that followed to try to live up to his example," Obama said.

"When I was elected President of the United States, I hugged him on the inauguration stand before I was sworn in and told him I was only there because of the sacrifices he made," Obama added.

Mourners view a makeshift memorial to the passing of the late Rep. John Lewis, a pioneer of the civil rights movement and long-time member of the US House of Representatives, under his mural in Atlanta, Georgia, US. July 18, 2020. [File, Standard]

President Donald Trump said he was saddened by the news of the death and that he sent his prayers to Lewis and his family. In 2017, Lewis rebuked Trump’s election, saying he did not recognise him to be a "legitimate" president.

Albeit, before Trump reacted to the death, he ordered that flags at the White House and on federal buildings be lowered to half-staff throughout Saturday to honour Lewis.

Joe Biden, the presumptive Democratic nominee for president, expressed his reverence for the political icon, saying he knew of no man with more courage than Lewis.

"When I saw him, I couldn’t help but think one thing: "I haven’t done enough." May his life and legacy inspire every one of us to strive for justice, equality and what is right," Biden said in a statement.

We are made in the image of God, and then there is John Lewis. He was truly one-of-a-kind, a moral compass who always knew where to point us and which direction to march. To John’s family, friends, staff, and constituents, Jill and I send you our love and prayers. — Joe Biden (@JoeBiden) July 18, 2020

Hillary Clinton, the 2016 Democratic presidential candidate, called Lewis "the truest kind of patriot."

New York City Mayor Bill de Blasio described Lewis as a "a saint who walked among us."

French President Emmanuel Macron said, "A lifetime of struggle for civil rights. A lifetime of getting into 'good trouble,' of fighting for a world that is more just. A true hero. Indeed, 'because of you, John.'" 

Talk show host Oprah Winfrey tweeted, "Last week when there were false rumours of Congressman John Lewis’ passing, Gayle [King] and I called and were able to speak with him. He sounded weak but was surprisingly more alert than we expected."

Last week when there were false rumors of Congressman John Lewis’ passing, Gayle and I called and were able to speak with him. He sounded weak but was surprisingly more alert than we expected. pic.twitter.com/8kRRDMTvFm — Oprah Winfrey (@Oprah) July 18, 2020

Civil rights activist Rev Jesse Jackson, who first met Lewis during protests in 1960, said, "John Lewis is what patriotism and courage look like."

Sharing my reflections on the passing of @repjohnlewis. Rest in heavenly peace. #GoodTrouble. pic.twitter.com/jcA6OPm7Eh — Rev Jesse Jackson Sr (@RevJJackson) July 18, 2020

News agency AFP reported that Lewis was just 21 when he became a founding member of the Freedom Riders, who fought segregation of the US transportation system in the early 1960s, eventually becoming one of the nation's most powerful voices for justice and equality.

He was the youngest leader of the 1963 March on Washington, in which King delivered his famous "I have a dream" speech.

"Two years later Lewis nearly died while leading hundreds of marchers across the Edmund Pettus Bridge in Selma, Alabama when state troopers, seeking to intimidate those demonstrating for voting rights for black Americans, attacked. Lewis suffered a fractured skull that day, which would become known as 'Bloody Sunday'," AFP’s report read.

Lewis served 17 terms in Congress since he was first elected in 1986.