A suicide bomber blew himself up among a crowd of Shiite pilgrims passing through a mainly Sunni neighborhood in Baghdad and another detonated his explosives inside a cafe north of the capital, the deadliest of several attacks across Iraq on Saturday that killed at least 66 people.

The killings, which also included attacks on journalists and anti-extremist Sunni fighters, are part of the deadliest surge in violence to hit Iraq in five years. The accelerating bloodshed is raising fears that the country is falling back into the spiral of violence that brought it to the edge of civil war in the years after the 2003 U.S.-led invasion.

The extent of the carnage from the evening attack on the pilgrims became clearer as midnight approached, when officials sharply revised the death toll upward to at least 42. Another 80 were reported injured.

The bomber detonated his explosives at a checkpoint in the northern neighborhood of Azamiyah as the pilgrims en route to a prominent Shiite shrine in the nearby neighborhood of Kazimiyah, according to police officials. At least four policemen manning the checkpoint were among the dead, the officials said.

Azamiyah and the Shiite district of Kazimiyah sit on opposite sides of the Tigris River that snakes through the Iraqi capital. Their proximity made them a key flashpoint for the widespread sectarian conflict that gripped Iraq after Saddam Hussein’s ouster and peaked in 2006 and 2007. Authorities closed the bridge between the neighborhoods after hundreds of Shiite pilgrims died in a 2005 stampede sparked by fears of a suicide bomber, and reopened it in 2008.

Around the same time, another suicide bomber blew himself up in a cafe in the town of Balad, a largely Shiite town surrounded by Sunni communities about 50 miles north of Baghdad. Balad Mayor Malik Lefta said at least 13 people were killed and 22 were wounded in that attack.

He said the cafe was the same one hit by a deadly suicide bombing in August.

A hidden bomb also exploded inside a cafe in the religiously mixed Baghdad neighborhood of Baiyaa, killing three people and wounding 13, police said.

There was no immediate claim of responsibility for the day’s violence. Al-Qaida’s Iraq arm often deploys suicide bombers and targets Shiite civilians in an effort to undermine confidence in the Shiite-led government.

Earlier in the day, gunmen shot dead a reporter and a cameraman for the privately owned al-Sharqiya TV channel while they were working on a report in the northern city of Mosul, according to police. The city is a former Sunni insurgent stronghold that has been one of the hardest areas of Iraq to tame.

Al-Sharqiya identified the correspondent as Mohammed Karim al-Badrani and the cameraman as Mohammed Ghanem. It was not immediately clear why they were targeted.

Al-Sharqiya is one of several independent channels that took to the airwaves following the 2003 ouster of former dictator Saddam Hussein. It has drawn the ire of the current Shiite-led government with critical reports highlighting corruption, poor services and other shortcomings. Authorities suspended its operating license along with those of eight other Iraqi channels and pan-Arab broadcaster Al-Jazeera in April after accusing them of inflaming sectarian tensions.

The channel’s news director, Ali Wajih, said in a phone interview that he had not received any information from Mosul police, and he hoped the killings would be investigated.

“This is not new for al-Sharqiya. This is usual for Iraq, that they kill journalists,” he said, adding that 16 of the channel’s employees have been killed since 2003. Among them are four who were kidnapped and killed in 2008 while on assignment in Mosul.