While only the two arrests were announced, a third man was also being held, an Italian official said.
Italian officials and Jewish leaders said there was no indication of who might be responsible.
Other details emerged from both Italian officials and news media accounts.
But Italian officials acknowledge that it is unclear how such evidence would stand up in any court.
Italian officials had looked long and hard before making their decision.
But many Italian officials were clearly embarrassed by the military court's decision.
But now, some Italian officials are taking an exceptionally confident approach to the security challenge.
Italian officials have said they will probably agree to take in two of the Palestinians.
Italy has offered to lead the force and provide most of the soldiers for it, according to an Italian official here.
But Italian cultural officials are speaking of a deepening crisis.