BAGHDAD (AP) – U.S. Secretary of State Hillary Rodham Clinton said on Saturday that this week’s deadly suicide bombings in Iraq are a sign that extremists are afraid the Iraqi government is succeeding.

Making her first trip to Iraq as America’s top diplomat, Clinton said the country has made great strides despite the recent violence that killed at least 159 people on Thursday and Friday.

“I think that these suicide bombings … are unfortunately, in a tragic way, a signal that the rejectionists fear that Iraq is going in the right direction,” Clinton told reporters traveling aboard her plane ahead of her unannounced visit to Baghdad.

“I think in Iraq there will always be political conflicts, there will always be, as in any society, sides drawn between different factions, but I really believe Iraq as a whole is on the right track,” she said, citing “overwhelming evidence” of “really impressive” progress.

“Are there going to be bad days? Yes, there are,” Clinton said. “But I don’t know of any difficult international situation anywhere in the world or history where there haven’t been bad days.”

Clinton arrived a day after back-to-back suicide bombings killed 71 people outside the most important Shiite shrine in Baghdad. Those attacks came after Iraq on Thursday was rocked by its most deadly violence in more than a year when 88 people were killed by suicide bombers in Baghdad and Muqdadiyah, north of the capital. She was met at the airport by the chairman of the U.S. Joint Chiefs of Staff Adm. Mike Mullen, also on an unannounced trip to Baghdad, and the just-arrived new U.S. Ambassador to Iraq Christopher Hill, who presented his credentials to the Iraqi government late Friday.

Although the violence is at its lowest levels since the months following the 2003 U.S.-led invasion, the latest bombings come amid an increase in high-profile sectarian attacks that have raised concerns about the abilities of Iraq’s security forces. They have exposed gaps in security as Iraq takes over from U.S. forces in protecting the country and Iraqi Prime Minister Nouri al-Maliki has ordered a military task force to investigate the attacks as well as shortcomings that allowed the assailants to slip through.

Clinton said she would press the Iraqis with U.S. help to create a “nonsectarian security force that will not tolerate either sectarian actions or any kind of armed assault on the people of Iraq.” She is in Baghdad, following President Barack Obama’s brief visit earlier this month, to assure Iraqi authorities of the administration’s support even as it moves to draw down the U.S. military presence in the country. “We want the Iraqi people to know that the United States remains committed to helping them navigate through this period and have a better future,” she said, ahead of meetings with al-Maliki, President Jalal Talibani and Foreign Minister Hoshyar Zebari.

The Pentagon plans to hand over responsibility for most urban security in about three months as part of the administration’s goal of a complete exit of forces by the end of 2011.

U.S. officials say they are still committed to a June 30 deadline to move all forces outside major cities, including Baghdad. But the top U.S. commander in Iraq, Gen. Raymond Odierno, has said American troops could “maintain a presence” in some cities if requested by the Iraqis. Clinton, who made three trips to Iraq while she was serving in the Senate, is to begin her program in Baghdad with a closed-door briefing from Mullen and Odierno to discuss the uptick in violence.

“I want his evaluation of what these kinds of rejectionist efforts mean and what can be done to prevent them by both the Iraqi government and the U.S. forces,” she said.

Clinton saw the U.N. representative to Iraq and then met with Iraqi war widows. Later she answered questions during an unprecedented “town hall” style meeting with Iraqi aid workers and others at the U.S. Embassy.