The kidnappings prompted the aid group to suspend all of its operations in Gaza as a security precaution.
The was no immediate word on the identity of the kidnappers, whose actions were the latest in a string of abductions of foreigners in the lawless area.
The security officials, speaking on condition of anonymity because they were not authorized to talk with reporters, said the releases came without meeting any demands of the abductors.
The Popular Resistance Committees, a Hamas-linked militant group, claimed that it had negotiated the men's release. A spokesman for the group, identifying himself as Abu Mujahid, said Tuesday night that the two had been handed over unharmed to a senior official from President Mahmoud Abbas's Fatah party.
Claudio Moroni, 36, and Gianmarco Onorato, 63, were abducted in Deir el-Balah in central Gaza after their car was stopped by gunmen, the Red Cross said.
The kidnapping of the two men sparked an intensive effort to free them, with Palestinian security forces trying to track them down and Red Cross officials and Italian leaders calling for their release.
In Rome, Italian Foreign Minister Massimo D'Alema said he had given orders to "activate all possible channels" to obtain the release of the two men, and had taken some "personal initiatives" in that direction. He did not elaborate.
The incident also led the Red Cross to take the drastic step of suspending its activities in the poverty-stricken coastal territory. Iyad Nasr, a spokesman for the Red Cross's Gaza office, said the organization had ceased all field operations and would intervene only "in matters of life and death." Workers were ordered to stay in their offices because of fears for their safety, he said.
Over the past two years, there has been a rash of kidnappings of foreign aid workers and journalists in Gaza, usually by groups or families pressing the government for money or job guarantees. In most cases, the hostages were quickly released. None have been seriously harmed.