Hillary Clinton, the US secretary of state, has said that suicide bombings that have rocked Iraq are a sign that fighters are afraid the Iraqi government is succeeding in restoring security.

Clinton was speaking on Saturday to reporters in Baghdad, the Iraqi capital, on her first trip to the country as the US's most senior diplomat.

Despite deadly attacks that have killed at least 148 people in Iraq on Thursday and Friday, Clinton said the country had made great strides.

"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," she said.

"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."

'Bad days'

Clinton said there were going to be bad days, but "I don't know of any difficult international situation anywhere in the world or history where there haven't been bad days".

She arrived a day after suicide bombings killed 60 people outside the most important Shia shrine in Baghdad.

At least 88 people were killed on Thursday by suicide bombers in Baghdad and Muqdadiyah, north of the capital, in what is seen as Iraq's deadliest violence in more than a year.

Violence, which was high following the 2003 US-led invasion, has dropped off recently, but the latest bombings come amid an increase in high-profile sectarian attacks that have raised concerns about the abilities of Iraq's security forces.

The Pentagon will hand over responsibility for most urban security in about three months as part of the US government's goal of a complete exit of forces by the end of 2011.