By Marc Jones LONDON (Reuters) – Shares advanced cautiously on Monday as investors braced for a possible escalation in Ukraine’s civil conflict after anti-Kiev rebels declared victory in a referendum on self-rule. European stock markets got the week off to solid start, edging up in line with Asia early on, while the euro and euro zone government bond yields were pinned down by the European Central Bank’s signal that it is likely to cut rates next month. But tensions in Ukraine kept the mood cautious.