Egyptian President Mohamed Morsi told CNN in a Monday interview he aimed to raise the detention of Rahman, a blind Egyptian cleric tied to the terrorist attacks on the World Trade Center in New York City in 1993.
"I want him to be free," Morsi said.
Morsi said he'd press the issue during a possible visit to the United States before the end of March.
U.S. Rep. Mike McCaul, R-Texas, chairman of the Homeland Security Committee, said the move would in opposition to U.S. security interests.
"Releasing a terrorist who plotted against the United States and has American blood on his hands would be seen as a sign of weakness throughout the Muslim extremist world and will only serve to embolden our enemies who continue to plot against us," McCaul said in a statement.
Rahman, 73, is serving a life sentence at a federal prison in North Carolina.
Al-Arabiya reports that Morsi's position may be a political gesture to the Salafi political group Gama'a al-Islamiya. The group, which counts Rahman as a spiritual leader, renounced violence in 1997 and has emerged as a political force since the Egyptian revolution in 2011.