Both had been at the concert, waving rainbow flags.
As of Tuesday, at least 20 people in Egypt had received prison sentences ranging from six months to six years, the Egyptian Initiative for Personal Rights said, including four people who were sentenced Saturday to three years each.
The crackdown is the latest sign of the repression of political and social freedoms under the government of President Abdel Fatah al-Sissi.
A crackdown on gay people in Egypt intensified in recent days as security forces raided cafes in downtown Cairo and courts delivered harsh prison sentences, further driving the nation's LGBT community underground.
More than 60 people have been arrested, human rights activists said, since a concert last month by a rock group where some members of the audience waved a rainbow flag — photos of which went viral on social media and caused public outrage.
He added that those detained "should be put on an immediate trial because they deliberately aimed to use this event to claim Egypt is a country of homosexuality, and this is not true." Some were arrested for waving rainbow flags, and others for their Facebook posts.