At least 9 people were killed and more than 20 were wounded, Saturday, when a suicide bomber targeted members of U.S.-allied Sunni militiamen.  The explosion is raising questions about the capacity of Iraqi forces to maintain security.

The attack by a suicide bomber in the Iraqi town of Jbala, south of Baghdad was the most recent in a series of attacks that have killed dozens.

Officials said the bomber struck Saturday as a crowd of community security forces, known as the Sunni Awakening Councils,  were waiting outside a military building for their paychecks.

The Iraqi government has taken over payment for the Sunni militiamen, or Sahwa members, as they are known in Arabic, from the United States. Delays in paying them have caused severe friction with the Shi'ite-led government in recent weeks.

The Sunni militias include former insurgents who have turned against al-Qaida and other groups.  They have been credited with helping reduce violence in Iraq over the past year.

The Iraqi government, however,  has been suspicious of the fighters, maintaining that some retain ties to the insurgency.

There are some 90,000 Awakening fighters and their tensions with the government came to a head last month in central Baghdad when the arrest of one of their leaders triggered a shootout with U.S.-backed Iraqi forces.    

Prime Minister Nouri al-Maliki later said the government crackdown - which escalated into a two-day gunbattle - was not politically motivated but followed a six-month investigation that tied the commander to crimes and subversion.

More than 50 people were killed in violence in Baghdad alone, this week, marking a new wave of attacks, after a recent lull. The attacks are likely to call into question the ability of Iraqi forces to maintain security in the leadup to a planned U.S. withdrawal by August 2010.

Meanwhile, Iraqi Defense Minister Abd al-Qadir Mohammed Jassem, on a visit to Moscow with Prime Minister Nouri al Maliki, told reporters that his government hoped to buy more military equipment to strengthen Iraqi forces and reduce violence.

"We need major arms purchases, before the end of 2011, to meet our hopes and expectations and to maintain a good level of security inside the country and to be able to control at least 60 percent of our border," he said.

U.S. commanding General Raymond Odierno told The Times of London, in an interview this week that it was possible that US troops remain in several Iraqi cities, beyond the June 30 deadline, if violence continued.