BAGHDAD, Iraq (CNN) -- A messianic Shiite cult's battles with police and attacks on religious holiday pilgrims have left 75 dead across Iraq in two days, officials say.
Iraqi security officers inspect debris Saturday after a gunbattle during a Shiite commemoration in Basra.
Millions of pilgrims were walking in the streets throughout the country Saturday in observance of Ashura, a four-day commemoration of an early Shiite martyr, a grandson of Mohammed.
Seven people were killed and 17 wounded Saturday afternoon when a Katyusha rocket slammed into an Ashura gathering in Tal Afar in northern Iraq, said the city's mayor, Najim Abdullah.
A bomb hidden under a pile of trash in Kirkuk exploded Saturday morning near Shiites walking as part of the Ashura observance, killing at least two, an Iraqi police official said.
In addition, two people were killed and 10 wounded when a roadside bomb exploded near a popular restaurant in Baghdad's Sadr City neighborhood. It was unclear, however, whether the bombing was related to the religious commemoration. Sadr City has a large Shiite population.
The attacks came a day after at least 66 people died and at least 60 were wounded in fighting between Iraqi security forces and members of a violent Shiite messianic cult in two cities in southern Iraq, authorities said. Watch what set off the violence »
Cult members attacked pilgrims in Basra and Nasiriya as they were observing the holiday, particularly significant to Shiites, that commemorates the seventh-century martyrdom of Imam Hussein, a grandson of the prophet Mohammed.
Pilgrims stream to Shiite shrines in cities such as Najaf and Karbala. Some processions are marked by self-flagellation, skin-cutting and other displays of grief.
Iraqi authorities had imposed stiff security measures, including vehicle bans, because of past sectarian violence during Ashura, which ends Sunday.
National Security Adviser Mowaffaq al-Rubaie said the violence in the southern cities began about 2 p.m. Friday, when gunmen opened fire on pilgrims in Basra and Nasiriya.
Dozens of militants in five vehicles fired on pilgrims in Basra before taking over an oil facility, al-Rubaie said. Iraqi security forces cleared them from the facility and followed them to another section of Basra, where fighting ended Saturday, he said.
The leaders of the cult's Basra and Kut organizations were killed, he said.
Gunmen who attacked pilgrims in Nasiriya also tried to capture a police station, but they retreated after a fierce battle with police, al-Rubaie said. One gunman who was captured gave police information that helped them foil another planned attack, he said.
Later Friday evening, al-Rubaie himself was caught in the middle of another attack when he visited a mosque in Baghdad for an Ashura observance.
Al-Rubaie told CNN that gunmen fired on the crowd but security forces "managed to control them and apprehend them." There were no reports of injuries.
It was not clear exactly how many of the 66 dead and 70 wounded were pilgrims and how many were militants or police. It appeared that most of the dead were cult members, an official said.
Government spokesman Ali al-Dabbagh told CNN that the gunmen in Basra were followers of Ahmed al-Hasani al-Yamani. He said their Basra leader, Abu Mustapha Ansari, was among those killed.
"Misguided and perverse groups tried to take advantage of the atmosphere of forgiveness on this holy occasion," al-Dabbagh said. "These groups are exploiting religion and are promoting this perverse and misguided cult through violence."
While some confusion remained Saturday, al-Rubaie indicated that the Basra and Nasiriya attackers were connected to the same cult.
The fighting in Basra was an opportunity for Iraqi security forces -- who recently took over responsibility for security from the British -- to show their abilities.
The British Defense Ministry said Iraqi security forces dealt well with the incidents in Basra. British troops, based in southern Iraq, were not involved.
Prime Minister Nuri al-Maliki's office said in a statement that "security and military forces were able to impose full control and restore calm" in Basra and Nasiriya and that they arrested several attackers.
"Our security forces were able to crack down a ... network and arrest a big number of its members, who were planning to kill the religious scholars in Najaf and Karbala," al-Maliki's office said. E-mail to a friend
CNN's Mohammed Tawfeeq, Jomana Karadsheh and Yousif Bassil contributed to this report.