Clean your guns, the burly Iraqi commander told nearly 200 specially trained counter-terrorism troops arrayed in front of a dozen armored black Humvees: In an hour and a half, we leave for Mosul.
The troops listening closely to Lt. Col. Ali Hussein were among 35,000 Iraqi security forces leading a government offensive that began Monday to oust Islamic State from the city of Mosul, the extremist group's last major stronghold in Iraq.
"We depend on each other to move ahead. This is our decisive battle," Hussein said, warning of booby traps, suicide bombers and mines.
After dismissing his troops, Hussein said that although the army is leading the battle for Mosul, it's working with Kurdish fighters known as peshmerga as well as Sunni and Shiite militias to capture and secure surrounding areas. The force is supported by a military coalition that includes the United States.
Mosul, which is believed to have about 1 million residents, was seized by Islamic State in 2014.
The battle to retake the city is expected to be difficult, involving urban warfare among a mix of factions and forces in a place still full of civilians. Iraqi forces, many of them Shiite, are expected to need some level of support by residents of the largely Sunni city for the offensive to be successful.
Troops massing at bases around Mosul in recent weeks began by encircling the city Monday in an attempt to prevent Islamic State fighters from fleeing. The counter-terrorism forces, which also led offensives in Fallujah and Ramadi, are expected to join other troops in storming the city.
About 4,000 peshmerga troops fought to secure nine villages surrounding Mosul on Monday, the first stage of the battle. The area had been home to Christians and other minorities persecuted by Islamic State, and many civilians had already fled, peshmerga commanders said.
The fighting began hours after Prime Minister Haider Abadi announced on state television about 2 a.m. that the liberation of Mosul had begun.
"The Iraqi flag will be raised in the middle of Mosul, and in each village and corner very soon," Abadi said, dressed in a military uniform and surrounded by officers.
By noon, peshmerga forces had cleared most of the villages, suffering fewer than 10 casualties, peshmerga Brig. Gen. Salar Jabar said as he stood with dozens of troops near the front lines about 20 miles east of Mosul.
Black smoke billowed on the horizon, where he said Islamic State militants had set fire to a gypsum plant to obscure the area from airstrikes. Soon after, several booms sounded. Some were airstrikes, he said, but they were also still seeing Islamic State suicide bombers, some as young as 13, and snipers.
"We are trying to liberate as much as we can," he said, but, he added, "They're resisting."
Though many Islamic State fighters have fled with their families to Syria, some villages still had 10 to 20, and they leave mines and booby traps behind, he said. At least three peshmerga, including a commander, were killed Monday by mines, fellow fighters said.
In a statement released online, Islamic State said it launched a series of suicide car bomb attacks against Iraqi forces.
Coalition warplanes carried out four airstrikes Sunday in and around Mosul against the militants' tactical units, weapons caches and supply routes, including a bridge and tunnel entrances, the Pentagon said. The U.S.-led coalition has launched more than 70 airstrikes in the Mosul area this month.
Most of the 5,000 U.S. troops in Iraq "are not anywhere close to the front line," Pentagon spokesman Peter Cook told reporters.
He said the U.S. is assisting the Iraqis with logistics support by sending supplies from remote bases, directing airstrikes from command hubs, or training Iraqi forces for other operations.
U.S. special forces are advising Iraqi and Kurdish commanders at makeshift headquarters around Mosul, however, and the facilities will move forward as the Iraqis gain ground on the battlefield.
"To be sure, Americans are in harm's way as part of this fight," Cook said.
Turkey, meanwhile, has stationed about 3,000 troops at a base near Mosul, and President Recep Tayyip Erdogan has insisted they participate in the liberation to prevent "Sunni-Shiite strife" in the city.
Officials and analysts said ahead of the offensive that sectarian tensions could flare once forces converge on Mosul.
Maj. Sarhard Raffat, standing near the front lines, said his Kurdish troops had been instructed by commanders not to enter Mosul, but to hold the perimeter and await Iraqi forces. That's what they intended to do, he said, as more booms sounded in nearby villages.
Peshmerga Division Commander Rashid Abdullah Hader stood with a fellow group of fighters perched on the back of a pickup truck with a machine gun mounted in the bed. They faced a dusty field of golden grass, scanning the plain where smoke still billowed below the surrounding mountains.
"I'm optimistic that all the people will get back to their families and their land and it will be a victory not just for Kurdistan, but for the Iraqi people," Hader said.
Kurdish forces have been flying their own flags and Hussein's forces are using Shiite sectarian flags, though officials say they are hopeful that will not cause problems.
"We had those flags on in the battle for Qayyarah [a Sunni area about 40 miles south of Mosul] and people didn't have any issue with it," Hussein said. "I'm sure the people of Mosul will understand. If they are not happy, we can take the flags down."
He stressed that "there were special conditions" for having sectarian militias participate in the fight. For instance, "they have to disappear and the Iraqi army has to take control" when the city is seized.
Some of the peshmerga and Iraqi soldiers have relatives and friends trapped in Mosul and other Islamic State territory.
Humanitarian groups have said the offensive will displace tens of thousands of residents, 200,000 in the first two weeks alone.
"With no clear safe routes out of Mosul, thousands are now in danger of getting caught up in the crossfire," said Aleksandar Milutinovic, director of the International Rescue Committee's operations in Iraq. "Civilians who attempt to escape the city will have little choice but to take their lives into their own hands and pray that they are able to avoid snipers, landmines, booby traps and other explosives."
Zirwa Abdal Rahim, a peshmerga fighter, 28, said Monday that he talked to a friend in Mosul, a car salesman, just before the offensive started. He said Islamic State leaders had been fleeing with their families west over the border to Raqqah, Syria, the de facto capital of Islamic State's self-styled caliphate.
"They are waiting for the security forces to tell them what to do," he said of the man's family, who had seen leaflets dropped by the coalition instructing them to shelter in place. "They know they have to stay in their houses. We have information that there are counter-terrorism groups in Mosul waiting for forces to get close so they can fight Islamic State."
It was in Mosul, at the city's Great Mosque, that the group's leader, Abu Bakr Baghdadi, declared their caliphate, including portions of Iraq and Syria.
Though some residents alienated from the Iraqi federal government welcomed them, they soon soured on the harsh regime, which meted out severe punishment for violating moral codes, with public executions and beheadings.
Residents are not allowed to have cellphones, although many hide them. They also have televisions and know the offensive is underway.
Thousands of the fighters stayed and appear ready to use civilians as human shields, Abdal Rahim's friend told him. They zoom around town on motorbikes, he said, forcing families to pay $200 each to fund their fight, digging ditches to halt troops' progress and "every time they hear warplanes, they are hiding among civilians."
Peshmerga blamed Islamic State for blowing up Mosul's Freedom Bridge over the Tigris on Monday, which connects the two sides of the city. The extremist fighters' media claimed the bridge was destroyed by a coalition airstrike.
Among black-clad soldiers in counter-terrorism caps preparing to roll out late Monday were young men from various corners of the country, including Sunnis, Shiites and other sects.
Mahmoud Essa Mohammed, 26, a Sunni, said he's from a village outside Mosul still controlled by Islamic State where residents have been providing the army with information to help the offensive.
"It will be a big victory for all Iraqis," said Mohammed, who said he didn't mind the sectarian Shiite flags flying from the Humvees.
Harth Falh, 22, came from largely Sunni Anbar province to the southwest, where the army managed to score a major victory recently in wresting Fallujah from Islamic State control. His family, like many across Iraq, is hoping for a decisive, symbolic victory that signals a way forward after years of battling Islamic extremists.
"My uncle said don't come home unless you raise the Iraqi flag in Mosul," Falh said, as the Humvees began to roll at sunset.
Times staff writer W.J. Hennigan in Washington contributed to this report.
3:10 p.m.: This article was updated with statements from the Pentagon and Islamic State.