WASHINGTON, March 6 (Reuters) - President George W. Bush insisted on Tuesday a new Iraq security plan is making gradual progress, despite the deaths of nine more U.S. troops and another major bomb attack. Bush used the bulk of a speech to the American Legion veterans organization to defend his plans to deploy 21,500 more U.S. troops to Iraq aimed at taking control of and holding restive neighborhoods of Baghdad rife with sectarian violence. Bush also said a regional conference in Baghdad next month will be "a test of whether Iran and Syria are truly interested in being constructive forces in Iraq." The United States has agreed to attend the conference but U.S. officials have said American representatives will not have side meetings with officials from Iran and Syria. Washington accuses Iranians of providing explosive devices to Iraqi insurgents for use against U.S. troops. Insurgents killed 112 Shi'ite pilgrims streaming to the holy city of Kerbala in attacks across Iraq on Tuesday, including more than 70 after suicide bombers blew themselves up in a street lined with tents. The attacks are likely to increase sectarian tensions between majority Shi'ites and Sunni Arabs that have threatened to plunge the country into all-out civil war. The U.S. military announced on Tuesday the death of nine U.S. soldiers in two bomb attacks north of Baghdad, the deadliest day for U.S. forces since they launched the security crackdown in the capital three weeks ago. "Iraqi and U.S. forces are making gradual but important progress almost every day and we will remain steadfast until our objectives are achieved," Bush said. Arguing against any congressional attempt to scale back the mission, Bush said: "The mission is America's mission and our failure would be America's failure." Bush called on lawmakers to avoid adding billions of dollars of unrelated domestic spending to a $100 billion budget request for the wars in Iraq and Afghanistan, saying Congress should approve it "without strings and without delay." White House spokeswoman Dana Perino cautioned against expecting immediate results from the security plan. "Our commanders are not taking their eye off the ball. We are going to have unfortunate days." she said.
