Iraqi government forces and allied Shiite militias began consolidating control over most of the city of Tikrit on Wednesday, declaring they were on their way to a strategically and emotionally significant victory in their nine-day offensive against Islamic State militants there.
On Iraqi state television and in countless videos uploaded to social media, pro-government forces could be seen hoisting the national flag and those of the militias in and around Tikrit, a hub of the so-called Sunni triangle and the birthplace of Saddam Hussein, where Islamic State militants massacred more than 1,000 Shiite Iraqi soldiers from Camp Speicher last year.
Months after the Islamic State, also known as ISIS or ISIL, completely routed the security forces, the unfolding Tikrit offensive provided a first glimpse of Iraqi-directed forces committing to an all-out battle and handing the militants their first major setback in Iraq.
As if to show that they could still inflict pain elsewhere even as they lost ground in Tikrit, Islamic State militants mounted one of the fiercest assaults in months in the city of Ramadi, west of Baghdad. The militants set off 21 car bombs in and around the city, killing five and wounding scores, security officials said.
But Hikmat Suleiman, the political adviser to the provincial governor there, said that because of fortified defenses, and the defenders’ growing battle experience and improved intelligence, most of the bombs detonated before they reached their apparent targets.
With the government appearing close to completing the Tikrit operation, its largest since the militants swept into much of the country’s north and west last June, attention turned to what would come next and what it could mean for Iraq’s future. Revenge or abuses by the militias could worsen sectarian tensions, while a clean operation led by Shiites that frees Sunni residents from Islamic State rule could provide a measure of unity.
In Tikrit, for the first time, Shiite militia and government forces were coming face to face with the Islamic State militants around the scene of the massacres and the Sunni residents who had lived under them. They also began to uncover mass graves believed to hold the corpses of the soldiers slaughtered by the Islamic State last summer, with a total of 300 to 400 bodies found in two graves in and near the village of Albu Ajeel, south of Tikrit, according to a militia spokesman.
Depending on how these encounters play out, Iraqi officials may be able to claim a vindication of their strategy of taking the city with a force made up largely of Shiite militias, the strongest and most numerous force available after much of the army fell apart during the Islamic State onslaught last year.
American officials had expressed concerns about a heavily Shiite force taking a mostly Sunni area and about the leading role of Iranian military officials like Gen. Qassim Suleimani of the Revolutionary Guards Corps. But Iraqi officials had emphasized that how and with whom to fight the battle was their decision.
Iraqi leaders attending an annual forum in Sulaimaniya, in the semiautonomous Kurdistan region, followed the news of the battles with great interest on Wednesday, declaring in speech after speech that the highest stakes and biggest challenges would come after the Islamic State was defeated in Tikrit and elsewhere, and the time came to unify.
The immediate aftermath of battle could be assessed only through images from the pro-government forces and the journalists accompanying them, since much of the city and the surrounding villages is still a danger zone because of roadside bombs and traps left behind by the militants of the Islamic State. So those television and social media images were being closely followed by Iraqis.
While critics of the militias circulated images of burning houses in Albu Ajeel, other militia members uploaded videos of residents joyfully greeting them, and recorded numerous interactions with captured Islamic State fighters, as if to show what they were up against and to insulate themselves from allegations of abuse.
“This battle today has proven to the world that the Sunnis and Shia are united,” Naeem al-Aboudi, the spokesman for one of the main Shiite militias, also known as popular mobilization forces, said in a telephone interview from Baghdad.
His group, Asaib Ahl al-Haq, had taken control of the village of Albu Ajeel, where many militia members say they believe some residents helped Islamic State fighters kill the soldiers, while others helped soldiers escape.
He said that Sunni residents of the village had led militia members and security forces to the mass graves, and that some said that they had seen young men brought from Speicher later buried there. Health officials were to remove the bodies from the mass graves, he said, and photographs had been sent to Baghdad’s central morgue.
Mr. Aboudi insisted that his group had not burned any houses, and that Islamic State militants were responsible for the burning buildings seen in one video apparently taken by militia members as they drove through Albu Ajeel. A uniformed man by the side of the road is heard to say, “Burn them, burn them,” as the person who is apparently doing the filming is heard saying that the Asaib Ahl al-Haq militia was in control.
In Alam, another town near Tikrit, the mayor, Laith Hameed al-Jabouri, said in a telephone interview that he had entered the town along with local Sunni fighters and Shiite militia forces and found that the buildings, including his house, were already on fire. He blamed the militants.
“Would I burn my own house?” he said.
Several videos posted to the Internet showed residents welcoming the militia forces with ululations and hugs. In one, residents waved a white flag and fighters approached with their hands up, saying, “Don’t worry.”
In another, soldiers or militia members triumphantly ripped down Islamic State flags and raised an Iraqi one in their place, as one declared, using an Arabic acronym for the group, “This is the end of the dirty Daesh!”
Some Sunni residents in areas held by the Islamic State have said they would welcome the Shiite militias if they rid them of the militants’ harsh rule. Mr. Aboudi said that 3,000 Sunni tribal fighters had taken part in the battle for Tikrit, a higher number than the 1,000 cited by United States officials. In Anbar Province, which is predominantly Sunni, an additional 4,000 Sunni fighters have been mobilized against the militants, according to security and provincial officials.
Northeast of Tikrit, security forces, local Shiite militias and Sunni tribal fighters took over a police station, a gypsum factory, two oil fields and an Islamic State camp in the Hamrin hills and freed 34 local hostages on Wednesday, officials said.
“We will take revenge on the killers and the criminals,” said Sheikh Hatim al-Assi, a spokesman for the local fighters, adding that the Sunni tribal force would also help in the larger battle for Mosul and was “one hand” with Shiite and Kurdish fighters.
In Tikrit itself, security officials said government troops were still trying on Wednesday night to take control of two western neighborhoods and of Mr. Hussein’s former palaces on the Tigris riverbank, the scene of the massacre.
