* Summit set for March 29
* Iraq Qaeda threatens new wave of attacks against Shi'ites
By Yara Bayoumy
BAGHDAD, Feb 25 (Reuters) - Iraqi Prime Minister Nuri al-Maliki said on Saturday an Arab League summit would take place as scheduled in Baghdad next month, despite security fears after violence killed at least 60 people this week.
Maliki's announcement came after al Qaeda's affiliate in Iraq threatened a new wave of attacks against Shi'ite Muslims, whom the Islamist militant group accuses of persecuting Sunni Muslims in post-Saddam Iraq.
The Islamic State of Iraq, an umbrella group for al Qaeda-linked Sunni insurgents, claimed responsibility for a string of coordinated attacks that mainly targeted police forces in Shi'ite areas and killed at least 60 people across the country on Thursday.
The violence highlighted the threat al Qaeda and other militant groups continue to pose to vulnerable security forces after the withdrawal of U.S. troops in mid-December.
The summit has been twice delayed by regional turmoil and acrimony between Baghdad and some Sunni Arab Gulf states over Bahrain's crackdown on Shi'ite protesters a year ago.
Maliki said all Arab countries had agreed to attend the March 29 summit, including 13 kings and presidents.
"I thank these Arab countries frankly, some of whom said 'By god, we will go to Baghdad, even if on foot'," said Maliki in a speech to Iraqi researchers.
"Even after the attacks that happened some days ago, their aim was to give a message to prevent the summit from taking place, but thanks be to God, it did not have an effect."
Maliki said the Arab League had inspected security measures Baghdad had taken to secure the safety of dignitaries going from the airport to the meeting venue and back, which they "highly approved of and were satisfied with".
The Islamic State in Iraq warned that war between Sunnis and Shi'ites was inevitable.
"There is no way out of it and there is no swerving from it," the group's spokesman Abu Muhammad al-Adnani was quoted as saying in an audio message released by the U.S.-based SITE Intelligence Group late on Friday.
"Know that the coming stage is a stage of real confrontation and war against the despicable (Shi'ites), whether you like it or not."
The summit in Baghdad will take place as Sunni and Shi'ite powers jockey for influence in a region increasingly split along sectarian lines over the turmoil in Syria and Western sanctions against Iran.
Iraq has strong ties to Syria and Maliki enjoys strong support from Shi'ite Iran. (Writing by Yara Bayoumy; editing by Andrew Roche)