Palestinians, led by their top Muslim cleric, appealed to Iraqi insurgents on Wednesday to release four Western peace activists, saying three of them had spent time in the West Bank aiding the Palestinians. The four workers for the group Christian Peacemaking Teams - an American, a Briton and two Canadians - were shown in a video released Tuesday by insurgents in Iraq. While in the West Bank, American Tom Fox and the two Canadians demonstrated against the construction of Israel's separation barrier in the West Bank, helped Palestinian children to get through Israeli army checkpoints and pitched in with the olive harvest, Palestinians across the West Bank said Wednesday. "We demand that these aid workers be released immediately," said Mufti Ikrema Sabri, the Palestinians' top Muslim clergyman. "We tell them that these aid workers have stood beside Palestinian people and it's our duty now to stand beside them." Sabri said Islam opposes taking civilians hostage and said such kidnappings are "inhumane."