Some senior officials, including President Trump’s top counterterrorism adviser, Thomas P. Bossert, favor sending the pair to the military prison at Guantanamo Bay in Cuba, according to a U.S. official familiar with the matter. Last month, Trump signed an executive order keeping the facility open, allowing the United States to transport new detainees there.

But senior officials at the Pentagon and State Department as well as the families of American hostages killed by the group want the men brought to the United States for a criminal trial, said the official, who like others interviewed, spoke on the condition of anonymity to describe internal discussions.

No final decision has been made about how to handle El Shafee Elsheikh and Alexanda Kotey, who were detained in early January in eastern Syria by the Syrian Democratic Forces, a Kurdish-dominated group and U.S. ally fighting the Islamic State, senior officials said. Bossert has instructed officials to consider all options, they said.