Two suicide bombers targeted Shi'ite Muslims in Iraq on Saturday, killing 60 people on the eve of the anniversary of one of their imams' deaths, police and medics said on Saturday.
In the northern city of Mosul, unidentified gunmen shot two Iraqi television journalists dead as they were filming, security sources said.
No group immediately claimed responsibility for either of the bombings, but such attacks are the hallmark of Sunni Islamist al Qaeda, which views Shi'ites as non-believers and has been regaining momentum this year.
In Baghdad, a suicide bomber detonated his explosives at a checkpoint, killing 48 Shi'ite pilgrims on their way to visit a shrine in the Kadhimiya district, police and medical sources said.
Earlier on Saturday, another suicide bomber blew himself up inside a cafe in a mainly Shi'ite town of Balad, 80 km (50 miles) north of Baghdad, killing 12 people. The cafe was targeted in an almost identical bombing 40 days ago.
"I received the corpse of my cousin. It was completely charred and difficult to identify," said Abdullah al-Baldawi, whose relative was killed in the cafe bombing.
Relations between Islam's two main denominations have come under acute strain from the conflict in Syria, which has drawn fighters from Iraq and the wider Middle East into a sectarian proxy war.
More than 6,000 people have been killed in violence across the country this year, according to monitoring group Iraq Body Count, reversing a decline in sectarian bloodshed that had climaxed in 2006-07.
It was not clear who was behind the killing of the journalists, who worked for Iraqi television channel al-Sharqiya News, which is often critical of the Shi'ite-led government and is popular among the country's Sunni minority.
"They shot them in the chest and head, killing them instantly," said a security source who declined to be named.
Iraq is considered one of the most dangerous countries for journalists. According to the Baghdad-based Journalism Freedoms Observatory, 261 journalists have been killed and 46 kidnapped since 2003, the year of the U.S.-led invasion of Iraq.
Mosul, capital of the predominantly Sunni province of Nineveh, is a stronghold for Islamist and other insurgents.
A journalist from Mosul said insurgents in the city changed their tactics and targets from time to time, and may now have set their sights on journalists, after previous spates of attacks against traffic police and mayors.
"I will leave the city of Mosul and live in the outskirts until things calm down," said the journalist on condition of anonymity.
The Journalists' Syndicate denounced the killings as a "criminal act", demanding the authorities track down the perpetrators and do more to protect the media.
Nineveh governor Atheel al-Nujaifi condemned the killings: "It aims to muzzle the voice of people, the voice of righteousness".
Iraq's Sunni community has grown increasingly resentful of a government it accuses of marginalising their sect since coming to power after the U.S.-led invasion that vanquished Saddam Hussein in 2003.
Sunnis launched street protests in December after Shi'ite Prime Minister Nouri al-Maliki sought to arrest a senior Sunni politician. A bloody raid by security forces on a protest camp in April touched off a violent backlash by Sunni militants.
The United Nations Mission in Iraq said nearly 900 civilians were killed across Iraq in September, raising the death toll so far this year to well above the total for 2013.