By Khalid Farhan NAJAF, Jan 10 (Reuters) - Iraq's national security adviser said on Wednesday the country's most senior Shi'ite cleric had given his blessing to government efforts to disarm militants as it prepares to implement a major new security plan for Baghdad. U.S. commanders and Iraq's once dominant Sunni minority have made clear they want any crackdown to include not just Sunni rebels but militias loyal to powerful Shi'ite Islamists. Mowaffaq al-Rubaie said he had briefed Grand Ayatollah Ali al-Sistani on the security situation in Iraq, and particularly in Baghdad, during a meeting in the holy city of Najaf. The reclusive Sistani hardly ever makes public statements but is an influential figure behind the scenes and the spiritual leader of Iraq's majority Shi'ites. "His eminence Sistani recommended an emphasis on the implementation of the law without any discrimination based on identity or background," Rubaie told reporters. "He also asserted the need for weapons to be in the hands only of the state, and to disarm those holding weapons illegally," said Rubaie, who is himself a Shi'ite. Prime Minister Nuri al-Maliki announced on Saturday that he planned a major security plan to restore order in Baghdad, the epicentre of violence in Iraq. U.S. President George W. Bush is due to announce later on Wednesday plans to send more troops to Iraq, most of which are expected to be deployed in Baghdad. U.S. commanders say crucial to the Baghdad plan's success will be the Shi'ite-led government's determination to go after Shi'ite militias as well as Sunni Arab insurgents. Washington has identified the Mehdi Army, a militia loyal to Shi'ite cleric Moqtada al-Sadr, as the greatest threat to security in Iraq and has been pressing Maliki to take it on. Sistani has urged Shi'ites in the past not to employ violence, although the rise in sectarian bloodshed over the past year has highlighted the limits of his authority. The meeting with Rubaie comes just three days after Sistani met Sadr for the first time in over a year. Sistani is the sponsor of the United Alliance bloc to which Sadr, Maliki and the other Shi'ite political leaders belong. Asked if Sistani had given a green light to the Baghdad security plan, Rubaie said: "His eminence is not interfering in the details but we can say that he stressed that weapons should be only in the hands of the state." Asked whether he had discussed disarming the Mehdi Army with Sistani, Rubaie declined to comment. Rubaie said Sistani had also urged the government to help people driven from their homes by violence.