MANCHESTER, N.H. — The Republican Party’s presidential class called for aggressive steps to curb illegal immigration, seizing on a delicate political issue as more than a dozen White House hopefuls faced off in New Hampshire on Monday night for a pointed preview of the first full-fledged debate of the 2016 primary season.

All but three of the 17 major Republican candidates for president participated in what was essentially a debate lite, which — unlike Thursday’s nationally televised debate in Cleveland — didn’t have a cutoff for participation.

The candidates focused their criticism at Democrats instead of each other, yet Monday’s meeting offered a prime-time practice round for the GOP’s most ambitious, who appeared on stage one at a time. They addressed several contentious issues, immigration topping a list that included abortion, climate change and foreign policy.

Former Texas Gov. Rick Perry, who may not qualify for the upcoming formal debate, called the flow of immigrants crossing the border illegally “a serious wound.”

“You want to stanch the flow,” he said as his Republican rivals watched from the front row of the crowded St. Anselm College auditorium. On those immigrants who have overstayed visas, Perry charged, “You go find ‘em, you pick ‘em up and you send ‘em back where they’re from.”

Former Pennsylvania Sen. Rick Santorum went further, calling for a 25 percent reduction of low-skilled immigrants coming into the country legally.

“Everyone else is dancing around it. I’m going to stand for the American worker,” Santorum said.

Monday’s participants included seven current or former governors, four senators, a businesswoman, a retired neurosurgeon and one former senator. Billionaire businessman Donald Trump, who has dominated the GOP primary in recent weeks, is among the three major candidates who decided not to join.

Trump, who launched his presidential bid by calling Mexican immigrants rapists and criminals, declined to attend the New Hampshire event.

He cited criticism from the local newspaper host, yet he is expected to play a prominent role in Thursday’s formal debate, where only the GOP’s top 10 candidates — as determined by national polls — will be allowed on stage.

Monday’s event was broadcast live on C-SPAN and local television stations in Iowa and South Carolina — states that, along with New Hampshire, will host the first contests in the presidential primary calendar next February.