Israeli security forces were on high alert on Friday for fear of violence as the Palestinians begin marking the \"Nakba\" or \"catastrophe\" which befell them following Israel\'s establishment in 1948. \"The police are on high alert and we have deployed thousands of police officers in and around Jerusalem, as well as in the north,\" police spokesman Micky Rosenfeld told AFP. \"Border police and regular units have been deployed in and around the Old City, although we are not on the highest level of alert,\" Rosenfeld said. \"At the moment, we are not expecting anything but we just want to make sure there are no disturbances on the Temple Mount,\" he said, referring to the site housing the flashpoint Al-Aqsa mosque compound inside the Old City. The site is the holiest place in Judaism and the third holiest in Islam after Mecca and Medina, and a destination for thousands of Muslims who go there to pray every Friday. But police said in light of the anniversary, they would restrict access to allow in only men over the age of 45 who held blue Israeli identity papers. There were no restrictions in place for women. Palestinians and their Arab Israeli kin were on Friday expected to begin a series demonstrations and marches in the run-up to Nakba Day, which will be commemorated on Sunday. Activists behind \"The Third Intifada\" website have also urged Palestinians to join a new uprising and march towards homes which they fled from or were forced out of when Israel was created in 1948. Refugees in Egypt, Lebanon, Jordan and Syria were also to mark the anniversary from Friday onwards. Israeli police said in a statement that they would step up checks on anyone coming in from the West Bank to annexed east Jerusalem, saying: \"Police will act firmly to prevent any attempt to disturb public order by anybody.\" And the military said troops were also on alert. \"The army is prepared for any unusual event during the coming weekend,\" a spokeswoman told AFP. Israel celebrated the 63rd anniversary of its creation on Tuesday, in accordance with the Hebrew calendar. More than 760,000 Palestinians -- estimated today to number 4.7 million with their descendants -- were pushed into exile or driven out of their homes in the conflict that followed Israel\'s creation. Around 160,000 Palestinians stayed behind and became known as Arab Israelis. They now number around 1.3 million people, which is about 20 percent of Israel\'s population. Israel has always refused to allow the return of the 1948 refugees for fear that a massive influx would threaten the Jewish majority in Israel, which now counts some 5.8 million Jewish citizens.