Palestinian Presidential spokesman Nabil Abu Rdeina has denounuced a letter by Israeli Foreign Minister Avigdor Lieberman, revealed by Israeli newspaper Haaretz earlier today, in which he described President Mahmoud Abbas as an \"obstacle to peace.\". Abu Rdeina termed the letter \"provocative\" and incites violence and instability in the country, as well as considering it as meddling in the Palestinian internal affairs. The spokesman told Palestine News Agency (WAFA) that the Middle East Quartet have to take an immediate action against Lieberman\'s letter, which \"consists of provoking statements that inflame killing and violence.\" Abu Rdeina also called on Israeli Prime Minister Benjamin Netanyahu to denounce the letter, in which Lieberman called for Abbas\'s replacement, because \"it would not contribute anything to creating an environment of peace.\" Furthermore, he considered the situation as \"political bankruptcy and evidence of Lieberman\'s confusion\".