Iraqi political and religious leaders are set to meet with President Jalal Talabani, amid warnings the sectarian violence could spiral into civil war.
An interior ministry official said dozens of bodies were recovered in Baghdad and its suburbs.
It is not clear if all the deaths were related to the Samarra shrine bombing.
Iraqi police said the three journalists had gone to Samarra on Wednesday to report on the bombing and the angry demonstrations that followed.
"The bodies of the presenter Atwar Bahjat, of cameraman Adnan Abdallah and of soundman Khaled Mohsen were found early this morning some 15 kilometres north of Samarra," police said.
They were kidnapped last night as they were leaving town.
A fourth person travelling with them was able to escape, police said.
At least 27 Sunni mosques were torched in Baghdad, after suspected al-Qaeda linked militants on Wednesday morning bombed the 1,000-year-old Imam Ali al-Hadi mausoleum, one of the country's main Shiite shrines.
The attack prompted global condemnation and appeals for calm, however these were ignored as large-scale demonstrations turned violent, leading to the killings of at least six Sunnis in the capital and attacks on a number of Sunni mosques nationwide.
Two people were also killed in an attack on offices of a Sunni political party in Iraq's mainly Shiite city of Basra, while gunmen stormed a prison in the southern port city and lynched 10 suspected Sunni militants from Egypt and Saudi Arabia.
The latest bloodshed comes as Shiite and Sunni political factions continue to bicker over the formation of a national unity government, amid anxiety that further delay in setting up a cabinet could lead the country into chaos.
The bomb attack on the shrine destroyed the dome of one of the Shiite Islam's holiest shrines where Shiites believe their 12th Imam disappeared in the 9th century.