NEW YORK — The families of people killed in the Sept. 11 attacks have been invited to military installations in four states to watch pretrial hearings in Guantanamo Bay, Cuba, for five men charged with planning or assisting the terrorist strike.

The hearings, which begin Monday, are closed to the public, but relatives who register in advance can watch on closed-circuit television at forts in New Jersey, Massachusetts, Maryland and New York City.

The suspects on trial before the military commission include Khalid Sheikh Mohammed, the self-professed mastermind of the Sept. 11 attacks.