'We stand by you': Obama speaks to Cuban dissidents ahead of meeting with Raul Castro
President Barack Obama waves after taking part in the CEO Summit of the Americas at a hotel in Panama City on April 10, 2015. (AFP)

US President Barack Obama met two Cuban dissidents Friday, ahead of a historic meeting with the communist regime's leader, Raul Castro.

Obama held a closed-door meeting with prominent critics of Castro's regime, as well as a dozen other dissidents from the Americas, in a move sure to provoke ire in Havana.

Obama -- flanked by the leaders of Costa Rica and Uruguay -- met lawyer Laritza Diversent and political activist Manuel Cuesta Moura.

The gathering took place on the sidelines of a civil society meeting linked to the Summit of the Americas in Panama.

Before the closed-door meeting, Obama told rights activists from across the region that "(we) stand by you every step of the way."

"When we speak out on behalf of somebody who has been imprisoned for no other reason than because they spoke truth to power, when we are helping an organization that is trying to empower a minority inside a country get more access to resources, we're not doing that because it serves our own interests," Obama said.

"We're doing it because we think it's the right thing to do."