(CNN) -

The national controversy over a surge of Central American immigrants illegally crossing the U.S. border established a new battleground this week in a small Southern California town, where angry crowds stopped detained migrants from entering their community.

The sentiment carried over to a raucous Wednesday night meeting at a Murrieta high school auditorium. Border Patrol and immigration officials got an earful.

"This is an invasion," attendee Heidi Klute said before a full house. "Why isn't the National Guard stopping them from coming in?"

The overflow crowd of hundreds spilled out into the school's parking lot.

In a faceoff Tuesday with three buses carrying the migrants behind screened-off windows, demonstrators chanted "Go back home!" and "USA," and successfully forced the coaches to leave Murrieta.

The buses instead took the 140 or so undocumented immigrants to U.S. processing centers at least 80 miles away, in the San Diego and El Centro areas, federal officials say.

Counterprotesters squared off with the demonstrators, and a shouting match erupted over the nation's immigration system, which recently has been overwhelmed with a tide of Central American minors illegally entering the United States alone or with other children.

Local politicians appear to be in lockstep with their constituents.

"It's a nationwide problem, and little ol' Murrieta has taken the lead," said Mayor Alan Long.

Riverside County Supervisor Jeff Stone got a rise out of the crowd, asking them to hold the White House accountable.

"Petition Obama to stop using these refugees to satisfy a political agenda," he said.

Root of the problem

A mix of poverty, violence and smugglers' false promises is prompting the Central American inflow.

Unlike undocumented Mexican migrants, who are often immediately deported, the Central Americans are detained and processed by the U.S. government, and eventually released and given a month to report to immigration offices. Many never show up and join the nation's 11 million undocumented residents, says the National Border Patrol Council, the union representing Border Patrol agents.

The Latin American immigrants rejected by Murrieta protesters were initially held in Texas, where U.S. facilities are so overflowing that detainees are sent to other states for processing.

The government doesn't have the room to shelter the children with adults: There's only one family immigration detention center, in Pennsylvania. To assist the unaccompanied children, President Barack Obama's administration opened shelters last month on three military bases, because federal facilities more designed for adults were overrun with minors.

Tuesday's busloads of detained Central American immigrants didn't include any unaccompanied minors, said Murrieta Police Chief Sean Hadden, who put the number of protesters at 125. The children on the buses were apparently in the company of relatives or other adults, said an official with the National Border Patrol Council.

'Deport! Deport!'

The protesters -- who shouted "Impeach Obama!" and "Deport! Deport!" -- confronted the buses a day after the town posted a notice on its website: "Murrieta Opposes Illegal Immigrant Arrival."

"This is a failure to enforce federal law at the federal level," Long said in a statement Monday about the pending arrival of the 140 immigrants at the U.S. Border Patrol station. "Murrieta continues to object to the transfer of illegal immigrants to the local border patrol office."