WASHINGTON, Dec 1 (Reuters) - U.S. President George W. Bush will hold White House talks with a top leader of Iraq's majority Shi'ites on Monday, days after having met Iraqi Prime Minister Nuri al-Maliki in Jordan, the White House said. Talks with Abdul Aziz al-Hakim, head of the Islamist SCIRI movement, appeared to signal more direct engagement by Bush to calm sectarian violence in Iraq that many believe already constitutes civil war.