Sen. Marco Rubio (R-Fla.) speaks in Washington on June 13. (Charles Dharapak/AP)

Sen. Marco Rubio (R-Fla.) declined to criticize President Obama for shaking hands Tuesday with Cuban President Raul Castro at a memorial service  in South Africa Tuesday for Nelson Mandela.

But the senator suggested that Obama should have lingered a little longer.

"I'm more focused on policy than some moment, but I thought that if he was going to be there and he was going to shake his hand, he should have asked him about these basic freedoms that Mandela is associated with that are systematically denied in Cuba," Rubio told reporters.

Rubio, a Cuban American, is a frequent, vocal critic of the Cuban government. He also has criticized the Obama administration for granting U.S. visas to Castro and members of his family to attend meetings at the United Nations and other events in the United States.

At a memorial for former South African president Nelson Mandela, President Obama greeted world leaders, including Cuban President Raul Castro. (Thomas LeGro/The Washington Post)