"I call on Abu Mazen to immediately head to Gaza and declare a consensus government that includes all Palestinian factions and political powers to confront the U.S. policies," Dahlan said, using an alternative name for Abbas.
"Go to your people and strengthen your position through them ...Then you will be able to confront the entire American administration."
Abbas hasn't traveled to the Gaza Strip since 2007, when rival Palestinian faction Hamas ousted the Fatah-linked PA. Other PA leaders, though, have visited the region.
Majed Abu Shamala, a supporter of Dahlen's, also spoke against Abbas' efforts to cut the salaries of PA employees and budgets in Gaza.
"In whose interest is it to threaten people with their salaries and their means of living?" Shamala said.
Thousands of Dahlen's supporters attended the rally, waving yellow flags.
In October 2017, Fatah and Hamas brokered a reconciliation deal in which the PA would have administrative control over both Gaza and the West Bank, but the implementation of that deal has stalled over weapons.