The success of a new security crackdown in Baghdad will be measured largely on how well the U.S.-backed government capitalizes on any respite of sectarian violence, Secretary of State Condoleezza Rice said Saturday.
Rice made an unannounced visit to the Iraqi capital to check on the early days of the campaign to put down tit-for-tat violence between Sunnis and Shiites.
Insurgent violence remains a concern. Rice's plane circled the airport for 30 minutes before landing because of military action in the city.
"If in fact militias decide to stand down and stop killing innocent Iraqis ... that can't be a bad thing," Rice told reporters traveling with her.
"But how the Iraqis use the breathing space that that might provide is what's really important," she said.
Rice was speaking with American troops and U.S. Embassy personnel before a meeting with Iraqi Prime Minister Nouri al-Maliki.
Rice is the highest-level U.S. official in Iraq since the recent start of a massive security operation in the Iraqi capital.
The visit was not previously announced as part of her trip to the Middle East. Rice is scheduled to meet later Saturday in Jerusalem with Israeli Foreign Minister Tzipi Livni.
She told the U.S. forces and diplomats that their work was worthwhile in helping Iraq and securing the safety of the U.S. at the same time.
"When you see Iraqis toiling and squabbling and struggling ... remember it's not easy to build a democracy," Rice said.
Rice will get an update on the security operation begun just days ago from U.S. generals, but she told reporters that the campaign appeared to be off to a good start.
U.S. officials here have said it is too soon to know if a reduction in civilian killings is due the campaign, or whether militias are lying low to wait out its early phase.
In Washington, the House of Representatives on Friday passed a nonbinding resolution voicing opposition to President Bush's decision to send 21,500 additional troops into Iraq. The Senate was to meet in a rare Saturday session to consider a similar measure.