Muqtada al-Sadr, a prominent Iraqi Shia leader, has blamed the recent surge of violence on US plans to withdraw its troops from Iraqi streets.
Officials have said the renewed attacks will not affect their plans and that American troops remain scheduled to pull out of all Iraqi cities by Tuesday.
On Thursday, Nuri al-Maliki, the Iraqi prime minister - speaking in the wake of recent bombings - insisted the country's security forces were capable of protecting citizens after US forces pull out.
"We assure you of Iraqi forces' readiness for the mission, despite some security violations, and we assure you that we are now more stable and steady," he said.
Al-Maliki said the attacks were part of a plan to "awaken sectarianism and create chaos, and prevent the Iraqi people from standing on their own feet".
Saleh al-Mutlaq, a Sunni member of the Iraqi parliament and the leader of the Iraqi National Dialogue Front, told Al Jazeera: "Iraqis have a right to be scared, they know very well that the withdrawal of American troops from Iraq will leave a political vacuum in the country.
"This is an irresponsible withdrawal from Iraq ... Al-Maliki is not aware of the consequences after the American troops leave the country"
Saleh al-Mutlaq, leader of the Iraqi National Dialogue Front
"This is an irresponsible withdrawal from Iraq, because there is not much change in the political process or the American policy in Iraq adopted by the previous US administration.
"Al-Maliki is not aware of the consequences after the American troops leave the country, he wants to deliver what the Iraqis want - an end to the occupation," he said.
US forces are also due to withdraw from all cities and major towns of Iraq by the end of June, including Mosul and Kirkuk, where violence levels remain persistently high.
A "small number" of US troops would be left in some Iraqi cities after the June 30 deadline at so-called Joint Security Stations to train and advise local security forces, a military spokesman said.
The US military will also continue to provide intelligence and air support to Iraqi security forces.