Keller also shared screenshots of messages that had allegedly been sent to other women.
The Egyptian FA subsequently took the decision to axe the player from their squad midway through the tournament, which they are hosting, but made no reference to the allegations in their statement.
After Warda's dismissal from the squad, Salah shared a post on his own Twitter account, in which he condemned the mistreatment of women but also called for a "second chance".
"I also believe that many who make mistakes can change for the better and shouldn’t be sent straight to the guillotine, which is the easiest way out."
The Liverpool forward then added in a second tweet: "We need to believe in second chances... we need to guide and educate. Shunning is not the answer."
Another Egypt player, Ahmed Elmohamady, gave a show of support for Warda by signalling his team-mate's No.22 with his fingers when celebrating his goal against DR Congo, and claimed "no player should be held accountable" for crimes committed off the pitch.
"Amr Warda is one of us and we all make mistakes. We will not leave Warda alone,” the Aston Villa player told reporters. "Warda represented Egypt on many occasions before, and what we should do is to stand by him.
"No player should be held accountable for anything done outside the pitch. We support Amr Warda."
Warda was a second-half substitute in Egypt's opening game against Zimbabwe, which the host nation won 1-0.
Egypt have already qualified for the last 16 having won their first two group games and face Uganda on Sunday in their last match before the knock-out phase.
Salah netted a stunning 43rd-minute strike in their 2-0 victory over the DR Congo on Wednesday.
Egypt lost all three of their group games, including a defeat to Saudi Arabia in their final match.