(Adds suicide bombing, Sahwa killed)
TIKRIT, Iraq, Oct 5 (Reuters) - A suicide bomber blew himself up inside a cafe in a mainly Shi'ite town north of the Iraqi capital on Saturday, killing at least 12 people, police said.
Separately, unidentified gunmen shot two Iraqi television journalists dead as they were filming in the northern city of Mosul, security sources said.
No group immediately claimed responsibility for the bomb attack, but suicide bombings are the hallmark of Sunni Islamist al Qaeda, which views Shi'ites as non-believers and has been regaining momentum this year.
The bombing in Balad, 80 km (50 miles) north of Baghdad, follows an almost identical attack on the same cafe 40 days ago.
"I received the corpse of my cousin. It was completely charred and difficult to identify," said Abdullah al-Baldawi.
It was not clear who was behind the killing of the journalists. Mosul, capital of the predominantly Sunni province of Nineveh, is a stronghold for Islamist and other insurgents.
The journalists 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.
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 journalists and the media.
Nineveh governor Atheel al-Nujaifi condemned the killings: "It aims to muzzle the voice of people, the voice of righteousness".
Violence, much of it blamed on al Qaeda, has killed more than 6,000 people this year, according to the monitoring group Iraq Body Count, reversing a decline in sectarian bloodshed that had climaxed in 2006-07.
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.
In recent months, attacks have increased on members of a government-backed Sunni militia known as the "Sahwa" that helped U.S. troops rout al Qaeda in 2007. Three Sahwa fighters were killed in a roadside bomb explosion south of Baghdad in Yousufiya on Saturday police said.
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. (Reporting By Raheem Salman and Ghazwan Hassan; Writing by Isabel Coles; Editing by Janet Lawrence)