US and Iraqi troops are conducting a major security crackdown in the Iraqi capital.
After Saturday's truck bombing, local residents said the imam of al-Falahat mosque had criticised the Sunni-led al-Qaeda in Iraq during Friday prayer sermons.
"Peace in Iraq will happen when citizens realise that they can express their ideas and views more effectively... than with violence"
JBernar5, Toledo, USA
Send us your views
Some Sunni tribal leaders in Anbar are leading a campaign to fight al-Qaeda, which is deeply entrenched in the province.
The Habaniya attack will be seen by many as an escalation of the power struggle in an area where US troop reinforcements are soon to be deployed.
The truck, filled with building materials such as stone and plaster board, was blown apart as worshippers left following mid-afternoon prayers.
Rescuers, including US soldiers, pulled survivors from the debris.
The US military sealed off the area and said it opened its medical facilities to "the most life-threatening injuries" among the more than 60 hurt.
Also on Saturday, at least 14 people were killed in bombings around Baghdad, most targeting Shia areas.
Armed men earlier stormed an Iraqi police checkpoint near Baghdad airport, killing eight policemen in a bold challenge to the security crackdown in the capital.
The attack in an area not far from the main US military headquarters in Baghdad underlined the hurdles faced by Iraqi security forces who are often outgunned by increasingly sophisticated fighters.
Saturday's truck bombing in Anbar province came a day after US troops raided a factory complex in Falluja full of propane tanks and industrial chemicals that the military said could be used to make bombs.
|At least 14 Iraqis died in attacks on Saturday|
in mainly Shia areas around Baghdad [EPA]
Back-to-back bombings in the past week released chlorine gas and raised worries that Sunni fighters are experimenting with chemicals to boost the terror level of their attacks.
On Monday, two suicide bombers in nearby Ramadi killed 11 people when they targeted the house of Sattar al-Buzayi, who has led the anti al-Qaeda drive, which is backed by the Shia-led government in Baghdad and the US military.
Al-Buzayi is backed by the Shia-led government in Baghdad and the US military.
Nevertheless, Nuri al-Maliki the Iraqi prime minister, expressed optimism about the 10-day-old security plan, saying US and Iraqi forces had killed around 400 suspected fighters since it started.
He visited the Baghdad operation's command centre on Saturday and urged security forces not to be swayed by sectarian loyalties.
He said 426 suspected armed fighters had been detained in the crackdown "and around that number have been killed" since it was launched in mid-February.