BAGHDAD  A series of bombs went off in Baghdad on Wednesday, extending a period of violence that has rattled Iraq’s government and security forces.

The pattern of Wednesday’s attacks  including three car bombs in predominantly Shiite areas and two at a Sunni mosque  raised fresh concern that sectarian passions could be inflamed anew.

Accounts of the death toll varied, from at least 17 people to as many as 48, with dozens wounded. So far in April, at least 300 Iraqis have been killed in bombing attacks, making it the bloodiest month since the start of the year and reversing the sharp drops in civilian deaths in January and February.

Prime Minister Nuri Kamal al-Maliki has blamed Sunni insurgents and members of Saddam Hussein’s ousted Baath Party for the recent violence, including four suicide bombings last week that killed almost 160 people, mostly Shiites. Mr. Maliki is torn between demands from the United States and some Sunni leaders to reconcile with some former members of the Hussein government and his Shiite partners, who reject an accommodation.