Egypt has offered to host intra-Palestinian peace negotiations next month in an effort to resolve the crisis between rival groups Hamas and Fatah.
Hamas leader Ismail Haniyeh earlier ordered the release of 20 political prisoners. He said the decision was a goodwill gesture aimed at facilitating negotiations with Palestinian President Mahmoud Abbas' Fatah movement.
"In order to provide a healthy atmosphere for dialogue, we decided to free all political prisoners in our custody in Gaza," he said.
Hamas arrested dozens of Fatah members last year. Pro-Abbas forces responded by launching similar crackdowns against Hamas in the West Bank.
Hamas previously said that Fatah members taken into custody in the Gaza Strip had committed criminal acts, and denied any political motivation in arresting them.
It has said that Fatah security services in the West Bank are holding 400 of its supporters.
