2 Iraq bombings kill more than 50

Coinciding with military efforts to curb the strength of Shiite Muslim militias in Baghdad and southern Iraq, the new attacks also portend the hurdles the Iraqi government may face as U.S. troop levels decrease through the summer. Iraqi troops will take on more responsibility for holding on to security gains made in the last year, and the challenge will be formidable if both Sunni and Shiite extremists are active.

The latest attacks occurred in Baqubah, the capital of Diyala province northeast of Baghdad, and Ramadi, the capital of Anbar province in western Iraq. Both were characteristic of the militant group Al Qaeda in Iraq, which has targeted public places with suicide attackers and car bombs to inflict widespread damage and casualties. Last month, there were 60 such attacks across Iraq, according to U.S. military figures. That represented an increase from 45 in February and 43 in January, the figures showed.

Attacks occur far less frequently than a year ago, before an additional 28,500 U.S. troops were sent to Iraq, but the steady increase of late appears to be a sign of the Sunni militant group's tenacity, an American military official said. As long as it is able to lure foreign fighters into Iraq with promises of financial rewards, and as long as Iraq's borders remain porous, Al Qaeda in Iraq will remain a threat, the official said. He spoke on condition of anonymity because he was speculating on security issues.

"Their strength is they can buy the talent they need," he said. "They've got a great deal of resilience."

At least 14 suicide bombings or car bomb attacks have been carried out this month, in addition to the incidents Tuesday and a bombing Monday near the Syrian border that killed 14 Iraqi soldiers.

U.S. military officials condemned the latest violence but said it should not be viewed as a sign that Sunni insurgents have regained the strength they had lost in the last year.

"This is the first suicide attack inside Baqubah in almost 90 days, and the overall violence in the city has decreased by 80% since June," said Maj. Mike Garcia, a spokesman for U.S. forces in Diyala province. Ramadi also has seen violence plummet from an average of hundreds of attacks a day in early 2007, to about two a day now, according to the military.