Kinshasa - Western powers have urged Democratic Republic of Congo to withdraw or re-draft divisive changes to electoral law due to be voted through on Thursday, after days of deadly protests over the legislation, diplomatic sources said.At least one woman was killed when police fired tear gas and live rounds to break up thousands more activists in the eastern city of Goma on Thursday, witnesses said. Police told Reuters only tear gas and sound grenades were used.Opposition groups and protesters say the planned legislation is a government ploy to delay national elections, currently scheduled for 2016, and keep President Joseph Kabila in power.At least 42 people have been killed in clashes with security forces, one campaign group said on Wednesday. The government, which denies any plan to delay elections, said 15 people, most of them looters, have died.Envoys from the United States, Britain, France and former colonial power Belgium met Senate President Leon Kengo Wa Dondo on Wednesday, a diplomat said, the day before a Senate vote on the legislation which has raised fears of further violence.Possible repercussion"They invited the president of the Senate to take into consideration the tension that was prevailing in Kinshasa and other towns of the country," the diplomat told Reuters, asking not to be named."They urged him either to suspend the modifying law or to remove the incendiary provisions," the diplomat said.The new law would order a census before the next election.The opposition says the census would take years to organise in a poor nation the size of Western Europe and would extend Kabila's rule beyond his 2016 term limit. The government has denied this.The ambassadors would meet the president of the national assembly Aubin Minaku on Thursday to convey the same message, the diplomat added."Kengo is very adamant to diffuse the situation. They [the government] are very aware of the possible repercussion," a second diplomat said.The electoral law was approved by the lower house on Saturday night.Opposition leaders and student leaders of the University of Kinshasa, the site of some of the fiercest confrontation, said they would wait for the Senate vote before deciding on their next move. The capital was largely quiet on Thursday.