WASHINGTON -- President Obama praised the Iraqi people for passing "an important milestone" as millions turned out for national elections despite attacks that killed more than 30 people. 

Obama noted that Iraqi security forces showed growing maturity in keeping violence from reaching much higher levels. The president is promising to stick by Washington's commitment to have all U.S. combat forces out of Iraq by Aug. 31. 

Obama said Iraqis and their government must remain on guard during "the long constitutional process" that follows as lawmakers take their seats in parliament to choose a prime minister and approve the new government. 

He said that process will take "not weeks, but months" and the danger of violence remains. 

Obama spoke Sunday in the White House Rose Garden several hours after polls closed in Iraq.