VATICAN CITY (AFP) - Palestinian president Mahmud Abbas met Pope Benedict XVI on Friday amid heightened tensions across the Middle East and Vatican concern about the treatment of Christian minorities in the region. This is the fourth time Benedict meets Abbas since becoming pope in 2005. The Vatican gave no indication as to the content of their discussions but the Middle East peace process has been a constant concern for the pope, who called for the creation of two states during a visit to the Holy Land in 2009. The pope has also voiced growing concern about the fate of Christians living in Israel and the Palestinian Territories, who currently represent just 1.5pb of the population. They were 25 percent in the 19th century. Abbas was at the head of a delegation that included Palestinian negotiator Saeb Erakat and religious affairs adviser Ziad al-Bandah. The delegation also met with Vatican Secretary of State Tarcisio Bertone. Revolutions across the Arab world have raised tensions in the region. Israeli police and army were on alert on Friday as the Palestinians geared up to mark 44 years since Israel seized the West Bank and Gaza Strip in the Six Day War. The anniversary, known in Arabic as the "Naqsa" or "setback", will be marked on Sunday when Palestinians in neighbouring Arab states say they are planning to march on Israel's borders as they did last month. On May 15, thousands of protesters in Lebanon, Syria and Gaza tried to force their way across the borders in a mass show of mourning over the 1948 creation of the Jewish state.