Khaled Ali, a former presidential candidate, was photographed and filmed making the ill-mannered gesture following Monday's ruling.
Special coverage of the 70-year-old billionaire's ascension to power
Saudi Arabia is putting on a brave face as US shale recovery looms, which could override global production caps and threaten to drive oil prices down even further.
Comment: The honeymoon is over for the Egyptian president, and his support may ebb away in the wake of the islands debacle, writes Robert Springborg.
Investigation: Obama may have won the Nobel peace prize, but escalated the drone warfare programme to unprecedented levels, reports Jessica Purkis and Jack Searle.
Analysis: Two years of squabbling over plunging prices almost disbanded the oil cartel, but after several non-OPEC countries got on board to limit production, OPEC's back in the game.
Monday's final court ruling over the Red Sea islands came amid public outcry at Sisi government's unpopular agreement with Saudi Arabia, reports Jo Schietti.
Saudis have called for international arbitration and even the expulsion of Egyptians after a court voided an agreement to hand over two Red Sea islands to the kingdom.
Saudi Foreign Minister Adel al-Jubeir said he was positive about the way the incoming US administration wanted to restore US influence in the world, contain Iran, and fight IS.
Arab football received a massive boost this week, as FIFA announced that the World Cup could be expanded to 48 teams giving countries in the region new hopes of competing.