Iraqi security forces work at the scene of a bomb explosion at an outdoor market in Baghdad’s northern Shaab neighborhood on Tuesday. (Khalid Mohammed/AP)

A string of bomb attacks hit Shiite areas of Baghdad on Tuesday, killing nearly 70 people and underscoring the deadly reach of the Islamic State into Iraq’s capital even as the militants face mounting pressures on their strongholds in Iraq and Syria.

In the past week alone, more than 200 people have been killed from bloodshed claimed by the Islamic State or said linked to the group.

The Islamic State asserted responsibility for the first of Tuesday’s blasts — all but one at open-air markets — but the subsequent attacks also appeared similar to last week’s blitz of bombings claimed by the group, including triple explosions in Baghdad on Wednesday.

Security officials and health workers said at least 69 people were killed — more than half of them in the Sadr City neighborhood that also took the brunt of last week’s attacks.

Three bombings have killed dozens of people and wounded scores more in Baghdad. The Islamic State is claiming responsibility. (Reuters)

“The bloody toll from these attacks, which is predominantly civilian, has been growing steadily over the past seven days,” said a statement from the rights group Amnesty International.

The signs of worry from Iraqi leaders also were clear. Prime Minister Haider al-Abadi ordered the arrest of the security official responsible for the Shaab neighborhood, where the first blast occurred, said a statement from Abadi’s office.

Influential Shiite cleric Moqtada al-Sadr blamed the government for its failure to protect civilians. Sadr has led weeks of street protests calling for reform and an end to corruption within the government.

There is “clear evidence that your government is unable to protect you,” Sadr said in a statement sent by his political coalition, al-Ahrar, on Tuesday.

“Your blood won’t go for nothing. Rebel against injustice and corruption,” he said.

The stepped-up violence from Islamic State militants coincides with widening military offensives by Iraqi forces backed by U.S.-led airstrikes in northern and western Iraq, the main bases for the Sunni extremist groups in the country.

In Baghdad’s northeastern Shaab neighborhood, a roadside bomb exploded outside concrete blast walls surrounding a market, security officials said, killing at least 11. As people aided the victims, a female suicide bomber detonated another blast, said Brig. Gen. Saad Maan, a police spokesman.

In Sadr City, explosives packed into a Kia truck detonated at a major square, killing more than 20, according to a statement from the Baghdad Operations Command. Gunmen loyal to the cleric Sadr were deployed in the neighborhood, which was also hit by deadly attacks last week.

In the following hours, explosions hit a fruit-and-vegetable market and a restaurant in Shiite areas of Baghdad, the Associated Press reported.

“The terrorists have struck again, adding to their long violent history of death and destruction and once again aiming to kill and maim as many innocent people as possible,” the U.N. special representative in Iraq, Jan Kubis, said in a statement.

Abadi said security forces have started operations to liberate the town of Rutbah in Anbar province in western Iraq. Iraqi troops have pushed Islamic State fighters from Anbar’s provincial capital, Ramadi, and other towns in recent months.

“Despite the many challenges faced by the country, our heroes are achieving victories and liberating land,” Abadi said in a statement. “God willing, we will bring news of victory soon.”

Cunningham reported from Istanbul. Brian Murphy in Washington contributed to this report.