In a meeting with organizations involved in inter-religious dialogue at the Notre Dame Jerusalem Center, Tamimi called upon Muslims and Christians to unite against what he said were the murderous Israelis.
Taking the podium after the pope without being on the original list of speakers scheduled for the evening, Tamimi accused Israel of murdering women and children in Gaza and making Palestinians refugees, and declared Jerusalem the eternal Palestinian capital.
Following the diatribe and before the meeting was officially over, the pope exited the premises. Army Radio reported that the pope shook Tamimi's hand before walking out.
Minutes after the embarrassing occurrence, Father Federico Lombardi, director of the Holy See press office, released a response to the incident.
"The intervention of Sheikh Tayseer Tamimi was not previewed by the organizers of the interreligious meeting that took place at Notre Dame Centre in Jerusalem," the message read. "In a meeting dedicated to dialogue, this intervention was a direct negation of what [it] should be," it continued.
"We hope that such an incident will not damage the mission of the Holy Father aiming at promoting peace and interreligious dialogue, as he has clearly affirmed in many occasions in this pilgrimage," Father Lombardi added.
"We hope also that interreligious dialogue in the holy land will not be damaged by this incident," the message concluded.
Last month, Tamimi reissued a warning to Palestinians against selling their homes or properties to Jews, saying those who violated the order would be accused of "high treason" - a charge that carries the death penalty.
Khaled Abu Toameh contributed to this report.