Palestinian prisoners rioted some three weeks ago inside the Jericho prison that Israel raided last week, underscoring the insecurity the unarmed US and British prison monitors felt there, British sources told The Jerusalem Post Wednesday. During the Israeli raid, carried out within minutes after the last of the US and British monitors at the prison had left because of security concerns, Israel apprehended some 40 of the prisoners there, including five men suspected of involvement in the killing of former tourism minister Rehavam Ze'evi. Both British Prime Minister Tony Blair and Foreign Secretary Jack Straw said last week that the Palestinians had been warned on a number of occasions that the unarmed monitors were at risk, and would be removed if the security procedures were not upgraded. Both the US and British consuls general in Jerusalem sent a letter to Palestinian Authority chairman Mahmoud Abbas on March 8 - six days before the raid - warning that the 14-man monitoring team would be pulled out of Jericho if the security situation did not improve for the monitors. According to the British sources, there were a number of riots at the prison in the past. The sources said the rioting three weeks ago wasn't directed at the monitors, who kept a watch from the prison's roof on the yard where Palestinian Front for the Liberation of Palestine head Ahmed Sa'adat and the others accused of murdering Ze'evi were held, but that since the men were unarmed, they felt vulnerable and insecure. The sources defined the rioting as "general unrest and frustration," with the inmates "being unruly and clashing with the guards." The sources said that in addition to the rioting, past attempts to "storm" the prison from the outside also added to a sense of insecurity and vulnerability. In addition, the sources said, this insecurity was heightened by "very specific" intelligence information received over the last few months regarding the danger of the monitors being kidnapped and held for ransom.