President-elect Barack Obama plans to issue an executive order on his first full day in office ordering the closing of the Guantánamo Bay detention camp in Cuba, people briefed by Obama transition officials said Monday.

But experts say it is likely to take many months, perhaps as long as a year, to empty the prison that has drawn international criticism since it received its first prisoners seven years ago this week. One transition official said the new administration expected that it would take several months to transfer some of the remaining 248 prisoners to other countries, decide how to try suspects and deal with the many other legal challenges posed by closing the camp.