Update at 7:34 p.m.
After a 50-minute speech and eight questions from a 2,200-member audience in the West High School gym, Trump wraps up his Sioux City event. He last campaigned in the city in May.
Update at 7:31 p.m.
Trump said as president he would approve the controversial Keystone XL oil pipeline, which has raised environmental concerns in South Dakota and Nebraska.
He also vowed: "We will support Israel 1,000 percent. ... That is the easiest question of the night."
update at 7:07 p.m.
At the 45-minute mark in his speech, Trump plans to take questions and brings up his poll numbers for the third time. He has slipped into second place among the GOP candidates in recent days as retired surgeon Ben Carson has risen to the top.
"Iowa, what the hell are you doing to me?" he asks.
"I have such an unbelievable relationship with the people of Iowa. I think I am going to win, I really do," he says.
Calling super PACs a "scam," Trump says candidates and the groups that funnel money to their campaigns cross boundaries they're not supposed to. "What do you think the chances they talk are? One hundred percent or 99 percent?"
Update at 6:49 p.m.
Trump promises to be "the greatest jobs president God ever created" but won't reveal his plan for dealing with ISIS because he wants to keep the jihadist group guessing.
Update at 6:47 p.m.
Trump tells crowd at West High School: "We shouldn't have been in Iraq. ... We totally destabilized the Middle East, we totally blew it."
Update at 6:20 p.m.
Trump begins rally by referring to his recent drop in the polls in Iowa, the first stop in the presidential nominating season for 2016.
"A little shakeup in Iowa. I don't know what's going on," Trump tells the audience.
He also gives a shout out to the big turnout for the rally.
"We have the biggest crowds, we have the most enthusiastic crowds," he said.
Trump promises to take questions from the audience after he finishes his speech.
Update at 6:10 p.m.
Trump campaign officials say the crowd in the West High School gym has now grow to more than 2,100. Another 100 could still be arriving as well.
Update at 6:05 p.m.
SIOUX CITY | A crowd estimated at 1,250 has turned out for GOP presidential candidate Donald Trump's rally at West High School, packing the bleachers in the Sioux City school gym.
The turnout is significantly bigger than events for other presidential candidates in Sioux City this year. The previous largest were in the 200 range.
Trump has landed in Sioux City and is expected soon to take the stage soon.
Our earlier story.
SIOUX CITY | By around 5:30 p.m., an estimated 650 protesters were congregated outside West High School, waiting for Republican presidential candidate Donald Trump to arrive.
The New York businessman and reality TV star is scheduled at 6 p.m. at a rally in the school gym.
Many of the protesters are current or former students, who argued Trump is divisive figure who has repeatedly made hostile statements about woman and immigrants.
Latinos make up about 29 percent of school's diverse population.
"With the comments he's made it's very unnecessary and caught the attention of many people, " Tania Espinoza, 24, a 2010 West High graduate.
Francisco Valadez, a 2012 West High graduate, circulated a online petition calling on the Sioux City school district to keep Trump off school property. More than 1,200 people had signed the petition as of Monday.
The Trump campaign paid $700 to use the high school. The city of Sioux City paid $2,100 for extra law enforcement, medical and fire responders. Ten Sioux City police officers are providing security.
At Monday's school board meeting, students said some of their peers had been harassed or bullied since Trump’s stop was announced. Superintendent Paul Gausman said hosting political rallies is permitted under the district’s facility use policy.
Opponents cited the school's anti-bullying policy as a reason to block Trump's visit.
The district is viewed as a national leader in anti-bullying policies, and West High was the location for some scenes in the award-winning documentary, “Bully.”