The Palestinian Authority announced on Monday that it had arrested a Hamas cell planning assassinations of Fatah leaders in the West Bank. The announcement was made by Secretary General Tayeb Abdelrahim, who declined to provide details of the arrests, including how many were made or what the targets were. He did say that the suspects have confessed to being ordered by Hamas leadership in the Gaza Strip to carry out attacks on “personalities and institutions of the P.A.” on July 7, the date set for the signing of a not-yet-agreed-upon unity agreement between Palestinian factions. The Palestinian Authority also announced on Monday that it was releasing 100 security prisoners as a gesture to encourage Egyptian efforts at mediating a unity agreement among factions. Although not specifically stated, it is believed at least some of those to be released are Hamas members.