At least 40 people were killed in a suicide attack claimed by the radical Sunni Islamic State on a Shiite shrine in northern Iraq, hospital officials said Friday.

Seventy-four were injured in the attack that targeted the shrine of Imam al-Sayed Mohammed bin Ali late Thursday in the town of Balad, around 80 kilometres north of the capital Baghdad.

The attack was carried out by three bombers who posed as members of the pro-government Shiite militia, the Popular Mobilization, and refused to show their ID cards as they entered the shrine, a senior police officer said.

Two attackers detonated their explosive vests at the main gate of the site, the officer added on condition of anonymity.

The third attacker lobbed two hand grenades in the courtyard of the shrine, which was packed with visitors before blowing himself up.

Authorities in the mostly Sunni northern province of Salah al-Din declared a curfew in Balad and two other towns in the province.

In an attempt to defuse sectarian tensions, Governor of Salah al-Din, Ahmed al-Jabouri, called on locals to stand united against the violence.

"Terrorism seeks to sow the seeds of discord and hatred among people of the province," al-Jabouri said in a statement.

Influential Shiite cleric Moqtada al-Sadr, meanwhile, ordered a militia force to go to Balad to protect the shrine and its visitors.

The attack came less than a week after a car bombing, also claimed by Islamic State, killed 292 people in Baghdad's central district of Karada, according to the Health Ministry.

Iraq's top Shiite cleric Ali al-Sistani Friday condemned both attacks.

He accused Islamic State of seeking to foment sectarian strife in the Shiite-majority country and called for "substantial changes" in the top echelons of the security apparatus.

"Being lax with the corrupt and failed [officials] at the expense of blood and lives of civilians has become unbearable," al-Sistani's representative Ali al-Safi said in a sermon at mosque in the holy city of Karbala. "There must be an end to it."

The government was heavily criticized for alleged security inefficiency after Sunday's bombing in Karada - the deadliest such attack in Iraq since the 2003 US-led invasion.

On Friday, al-Abadi sacked chief of the Baghdad Operations Abdul Amir al-Shammari and other security and intelligence officials in the city, state television al-Iraqiya reported. 

Since becoming prime minister in September 2014, al-Abadi, a Shiite, has sought to drum up the backing of the country's Sunni minority in the fight to dislodge the Islamic State out of Iraq.

The extremist Sunni Islamic State regards Shiites as heretics.

Late last month, Iraq declared "full liberation" of the western city of Fallujah from Islamic State.

The al-Qaeda splinter group still controls Mosul, Iraq's second largest city.

Related stories

Latest news

Syrian opposition rules out future role for President al-Assad

The Syrian opposition said Friday it would not accept any role for President Bashar al-Assad in the future of the war-torn country, reacting to a recent US shift saying that removing al-Assad is no longer a priority for Washington.

Russian Army integrates breakaway forces of Georgian province

Parts of the small fighting forces of the Georgian breakaway province of South Ossetia have been placed under Russian military control, Russian Defence Minister Sergei Shoigu said on Friday.

Czech Republic's Pilsner Urquell beer is now Japanese

Japanese brewing company Asahi completed its takeover of the Czech brewery Pilsner Urquell on Friday, Asahi said in a statement.

Judge approves 25-million-dollar settlement of Trump University case

A US district judge on Friday approved a 25-million-dollar settlement of lawsuits and state fraud allegations against Trump University, the US president's now-defunct business venture.

Former Thai premier Thaksin to junta on reconciliation: 'Cut me out'

Former Thai prime minister Thaksin Shinawatra on Friday announced that he is not interested in the junta-led reconciliation process, three days after the junta handed him a half-a-billion-dollar tax bill for his past business deal.

Dalic: We welcome possible deal between Agrokor and banks

The government welcomes the possibility of an agreement being concluded between the Agrokor food company and creditor banks, and the bill on vitally important companies is not a fallback plan but the result of the government's care for the overall economic and financial stability of Croatia, Deputy Prime Minister and Minister of Economy Martina Dalic told a press conference in Zagreb on Friday.

Croatia, China sign action plan for cooperation in agriculture

The Croatian and Chinese ministries of agriculture on Friday signed an action plan for cooperation in the field of agriculture for the period 2017-2018, the Croatian ministry said in a statement.

ZSE indices up, Agrokor shares in focus of investor interest

The Zagreb Stock Exchange (ZSE) indices on Friday rose by more than 1.8%, with stocks of the Agrokor food and retail concern being in the focus of investor interest again.

Berlin police defend handling of Berlin market attacker

Berlin police defended themselves on Friday against accusations that they stopped surveillance on Berlin Christmas market attacker despite knowing in June 2016 he was dangerous.

Croatia, creditors tailor emergency measures to save tottering giant

Croatia's tottering retail and food giant Agrokor reached an agreement with its creditors, putting its debts standby and allowing it to continue working during emergency restructuring, the Croatian branch of Austria's Erste Bank said Friday.

Agrokor's creditors say standstill agreement to go into force today

A standstill agreement regarding the Agrokor concern's existing financial obligations to banks will take effect on Friday, additional capital will be injected into the concern in the coming days and the concern will be actively restructured, which includes a change of its management, it was said on Friday after a meeting between Agrokor's suppliers and creditor banks.

Palestinians, UN slam Israel's new settlement plan

Palestinians, Israeli activists and the UN lambasted the government of Israeli Prime Minister Benjamin Netanyahu on Friday, a day after it gave the go-ahead for the first new West Bank settlement in a quarter of a century.

South Sudan rebels release three abducted foreign oil workers

South Sudanese rebels have released three foreign engineers they abducted in early March in the oil-rich Upper Nile region, Foreign Affairs Ministry official Mawein Makol Arik said on Friday.

Turkish opposition: Imprisoned party chief has gone on hunger strike

The head of Turkey's pro-Kurdish opposition party has launched a hunger strike from prison.

European leagues threaten Champions League schedule clashes

The European Professional Football Leagues (EPFL) on Friday threatened schedule clashes on Champions League matchdays in an ongoing dispute with the governing body UEFA.

Danish court revokes citizenship of IS volunteer

A Danish appellate court on Friday stripped a man of his Danish citizenship for volunteering to fight for the extremist Islamic State in Syria.

Banks and Agrokor agree on key elements of standstill agreement

Member banks of the coordinating committee of financial creditors and representatives of the Agrokor food company have in principle agreed on key elements of a standstill agreement, which is expected to be signed later today, announcing changes in the company's management team, Erste Bank said in a statement on Friday afternoon.

Syrian man on trial in Sweden; mosque attack labelled terrorism

A Syrian man went on trial Friday in the southern Swedish city of Malmo, charged with terrorism and arson after an attack last year on a building used as an assembly hall by Shiite Muslims.