Lewis, a Democratic congressman from Georgia, and Rep. Bennie Thompson, D-Miss., released a joint statement Thursday announcing their decision to skip Saturday's museum's opening, also citing Trump's attendance.
“After careful consideration and conversations with church leaders, elected officials, civil rights activists, and many citizens of our congressional districts, we have decided not to attend or participate in the opening of the Mississippi Civil Rights Museum," the congressmen said in the statement.
“After President Trump departs, we encourage all Mississippians and Americans to visit this historic civil rights museum," the congressmen added.
Jackson Mayor Chokwe Antar Lumumba was among the elected officials who attended the competing press conference during Trump's visit to the Mississippi Civil Rights Museum.
“It is my appreciation of martyrs both known and unknown that will not allow me to share the stage with a president who does not have a containing commitment to civil rights," Lumumba said at the press conference. “Mr. President, we don’t need you to tell us what civil rights means in Mississippi."
Dozens of protesters, some holding signs that read "Love Trumps Hate" and "Trump Trounces on Civil Rights," gathered outside the state-sponsored museum as the president arrived in Jackson for a private tour of the facility's exhibits.
Although his attendance was deemed controversial by civil rights leaders such as Lewis, Trump veered from any confrontation in his brief remarks inside the museum after the viewing.
"The civil rights museum records the oppression, cruelty and injustice inflicted on the African-American community, the fight to bring down Jim Crow and end segregation, to gain the right to vote and to achieve the sacred birthright of equality," he said at the museum. "And it’s big stuff. That’s big stuff."
Trump spoke broadly of the "heroes" of the American civil rights movement, without making a direct mention of Lewis. He also praised Martin Luther King Jr., describing him as a "man who I've studied and watched and admired for my entire life."
"Here, we memorialize the brave men and women who struggled to sacrifice, and sacrifice so much, so that others might live in freedom," Trump said. "Today, we pay solemn tribute to our heroes of the past and dedicate ourselves to build a future of freedom, equality, justice and peace."
ABC News' Alexander Mallin contributed to this report.