At least 120 Shia pilgrims were killed in twin suicide blasts on Monday.
On Wednesday, armed men fired on a group of pilgrims south of Baghdad, wounding two.
Moqtada al-Sadr, head of the Sadrist movement in Iraq, issued a statement urging pilgrims to join in chants and denounce the attackers.
"I ask almighty God to protect you from the sectarian sedition."
Outside the city, attacks have continued. Six Shia pilgrims were wounded in separate bomb and gun attacks south of Baghdad as they walked towards Karbala, police said.
In Baghdad, the new US commander in Iraq, general David Petraeus, said Iraqi forces had thwarted several car bomb attacks on the outskirts of Karbala.
The death toll of recent days has triggered concerns that the limited progress made by the Baghdad security plan of Nuri al-Maliki, the Iraqi prime minister, could be overturned by a new spate of killings.
Al-Maliki's government is due to hold an international conference hosting representatives from Iraq's neighbours and permanent members of the UN Security Council in the coming week.
The meeting will take place in central Baghdad at Iraq's ministry of foreign affairs to discuss the crisis in Iraq.
Delegates from Iran and the United States, who broke off diplomatic ties in 1980 and are currently in dispute over Tehran's nuclear programme and regional ambitions, are due to be present.
Last week, Sami al-Askari, al-Maliki's political adviser, said: "We will ask all neighbouring countries to stop interfering in Iraqi affairs and to put pressure on the armed groups with whom they have links to end the violence."
Saturday's conference will put senior officials from these countries around the table for the first time to discuss the crisis.