RAMALLAH  - The Palestinians began work on Tuesday to open the grave of iconic leader Yasser Arafat ahead of an exhumation of his body for a murder probe, a source close to his family told AFP.“Today they started removing concrete and stones from Arafat’s mausoleum and the work will last for almost 15 days,” the source said, speaking on condition of anonymity.“There are several phases,” he said, referring to the opening of the tomb ahead of a visit by French, Swiss and Russian experts to forensically test Arafat’s remains over suspicions he was poisoned with radioactive substance polonium.“It starts with the removal of stone and concrete and cutting the iron (framework) until they reach the soil that covers the body, which will not be removed until the arrival of the French prosecutors, Swiss experts and Russian investigators,” the source said. On Monday, Arafat’s mausoleum, which is located at the Muqataa presidential headquarters in the West Bank city of Ramallah, was screened off from public view with blue tarpaulins.The process of taking samples is expected to begin at the end of the month after the French and Swiss delegations arrive on November 26, officials have said.“Because of Arafat’s position and his status, no one will be allowed, under any circumstances, to photograph his body while the samples are taken,” the source told AFP.When Arafat died at the age of 75 in a French military hospital near Paris on November 11, 2004, French doctors were unable to say what had killed him.Many Palestinians are convinced he was poisoned by Israel. French prosecutors opened a murder inquiry in August after Swiss experts told Al-Jazeera television they had found high levels of radioactive polonium on Arafat’s personal effects.Polonium is a highly toxic substance rarely found outside military and scientific circles. It was used to kill former Russian spy turned Kremlin critic Alexander Litvinenko, who died in 2006 after drinking tea laced with the poison at a London hotel.On Tuesday, a source close to the French probe told AFP a court had handed a letter rogatory - a formal request for international judicial assistance - to the team of investigative magistrates who are to travel to Ramallah.