WASHINGTON -- Deadly mortars fall in the fortified Green Zone. The U.S. fires a Hellfire missile into a Shiite stronghold in Baghdad. Fighting escalates in Basra, where the mettle of Iraqi security forces are being sorely tested.

To President Bush, this could spell progress in Iraq.

The new flare-ups of violence threaten to roll back security gains and sway Bush's decision about further U.S. troop withdrawals. Yet, to Bush, they also show the Iraqi government and security forces' resolve to fight militias and outlaws.


"This is a defining moment, and it's a moment of where the government is acting," Bush said Friday at the White House. "And it's going to (take) a while for them to deal with these elements, but they're after it, and that's what's positive."

It's also a key juncture for Bush in the five-year-old war that has claimed 4,000 American lives, worn U.S. forces thin and dominated his presidency.

Bush said Prime Minister Nouri al-Maliki's crackdown in Basra against Shiite militias vying for control of the oil-rich region is a positive milestone in the birth of a democratic nation. Al-Maliki's decision to move against enemy elements in Basra shows "evenhanded justice" and the Iraqi government's willingness to go after both Sunni and Shiite insurgents and outlaws, he said.

The renewed violence threatened to unravel a fragile cease-fire with followers of radical Shiite cleric Muqtada al-Sadr.