U.S. agents in April detained an undocumented immigrant near Mission, Texas, close to the border with Mexico.
The number of people caught illegally entering the U.S. is up for a second straight year, according to federal data, adding fuel to the debate in Washington over whether the border should be better secured before any overhaul of immigration laws.
U.S. Border Patrol agents apprehended 388,422 people trying to enter without documents during the 11 months ending in August. That is already more than the 364,768 caught the year before, with a month still to go in the patrol's current fiscal year, which runs through September.
The largest increases occurred in Texas, which has accounted for more than half of apprehensions and is the current hotspot for human and drug smuggling along the Mexican border. "It obviously means more people are coming this way," said the patrol's Rio Grande Valley sector chief, Rosendo Hinojosa. Many of those caught are entering for the first time, he added.
Updated September 23, 2013, 7:45 p.m. ET
By MIGUEL BUSTILLO and MIRIAM JORDAN
The Wall Street Journal
The numbers are still far below the peak, from 1980 to 2005, when the Border Patrol averaged more than one million apprehensions a year. Migration from Mexico, which over the past four decades made up the largest immigration wave into the U.S. in modern times, shows no sign of reaching pre-recession levels, a report Monday by the nonpartisan Pew Hispanic Center said.
But after six years of declines, apprehensions have now risen for two years in a row despite the construction of a partial fence along roughly a third of the nearly 2,000-mile U.S.-Mexico border and a quintupling of border agents to more than 21,000 in the past two decades.
The rise in apprehensions is likely to underscore calls to better secure the boundary with Mexico before Congress allows those already here illegally to gain legal status or citizenship.
Some Republican lawmakers have said aggressive approaches, such as another doubling of agents or construction of a full border fence, should be part of any such measure, noting what happened in 1986, when Congress allowed people in the U.S. illegally to stay only to see more waves of illegal immigration.
An amendment included in the bill that passed the Senate in June boosted those efforts at a cost of $46 billion. But it was criticized as overkill by members of both parties, and the GOP-led House has thus far taken a different approach. A bill that cleared the House Committee on Homeland Security on a bipartisan vote called for crafting a border strategy before new money was committed.
"We have already spent some $75 billion on the border with relatively little to show for it," said Rep. Michael McCaul (R., Texas), chairman of the committee. "We don't just want to keep throwing money down there without a strategy."
House Minority Leader Nancy Pelosi (D., Calif.) is considering introducing a version of the Senate bill that strips out the amendment ramping up border security and swaps in the House panel's measure committing no money upfront until a border strategy has been established, a House Democratic aide said.
While it is unclear how the House will respond to the uptick in people caught entering the U.S., some experts believe it could lead to additional border-security spending in some form, as lawmakers seek to protect themselves from critics of immigration reform.
"Politically, border security is going to have to be a big part of any package, because it is a way for Republicans supportive of reform to cover their right flank," said Lanae Erickson Hatalsky of Third Way, a Democratic group advocating a middle ground on immigration.
Even in some of the Texas border counties most heavily affected by illegal crossings, there are mixed feelings about whether a further militarization of the boundary can solve the immigration problem. The Texas Border Coalition, a group of elected officials and business leaders, says the federal government should instead direct more spending to modernizing overcrowded ports of entry, which would speed trade as well as snare drug and human smugglers.
"When I look at Washington's approach to border security, I see so much wasteful spending," said Monica Weisberg-Stewart, a McAllen, Texas business owner who chairs the coalition's border-security panel. "I see a fence that has more gaps than barriers and other measures that are just funneling illegal traffic to our ports of entry."
The Pew analysis found that the size of the undocumented immigrant population in the U.S. rose to 11.7 million in 2012 from 11.4 million in 2010, partly due to the growth in migrants from Central America. Impoverished people from that region are now the fastest-growing group of illegal immigrants, federal officials and immigration experts say.
Demographer Jeffrey Passel, lead researcher of the Pew report, called the increase in undocumented immigrants statistically insignificant overall, and said that the more telling finding is that migration from more populous Mexico doesn't appear to be returning to former levels. The U.S. recession, tighter border security, drug-cartel violence and a lower fertility rate have discouraged migration from Mexico in recent years. Smaller families mean fewer working-age people putting pressure on that country's labor market.
Still, some areas along the border remain battlegrounds. They include Brooks County, Texas, an hour north of the border, where authorities have found the corpses of 76 suspected illegal immigrants this calendar year, on pace to approach last year's death toll of 129.
"Here we are, some 70 miles from la frontera, and we're still getting this type of traffic? It's crazy," said Brooks County Chief Deputy Sheriff Benny Martinez.
Mexicans still make up the majority of those caught trying to enter illegally. But what the Border Patrol calls OTMs—people from places other than Mexico—represented more than a third of total apprehensions so far this fiscal year. One of them was Donald Betancourth, 29 years old, who said he crossed the Rio Grande in April after a month-long journey from El Salvador atop a freight train laden with migrants. At the Texas border, he arranged for a smuggler to guide him across the river and take him to Houston for $2,500. But the smuggler left him and 19 others in the south Texas brush.
After three days without food, Mr. Betancourth said he surrendered to border agents. He is seeking asylum on grounds that he faces persecution at home because he is gay, and is out on bail in Houston while he awaits a response. "We risk everything to come here fleeing from problems and looking for a better life," he said. "But I decided that if they deport me, I will never make the trip back again."
More Central Americans are certain to continue trying to enter the U.S., driven by economic desperation and violence in their home countries, scholars said.
While Mexico has been beset by drug violence, some parts of Central America are even more dangerous. San Pedro Sula in northwestern Honduras had the highest murder rate in the world in 2012 according to the Mexico-based Citizens' Council for Public Security and Criminal Justice, which compiles worldwide homicide statistics.
Now that Central Americans are better established in the U.S., they help new arrivals find jobs and housing, and can afford to pay smugglers to sneak their relatives across.
"The Central Americans have a much more difficult time trying to survive [in their native countries] than the Mexicans, so they keep coming," said Néstor Rodríguez, a sociology professor at the University of Texas who studies Central American migration.