Immigration and Customs Enforcement, the federal agency charged with handling much of President Trump’s immigration crackdown, said it had arrested 7,400 people in nine days, significantly increasing enforcement. But details of those arrests have been scarce, leaving it unclear whether the criminals being targeted make up a significant share of those being captured.

ICE and the White House have highlighted a few dozen individual cases, posting criminal histories and photos of arrested immigrants to social media. For the remaining thousands of cases, no information has been made available.

U.S. Immigration and Customs Enforcement officers have conducted raids and arrests throughout the country in the days since President Trump took office.

Federal officials declined to share details on where most arrests took place, how many people had criminal backgrounds, or how many were ultimately detained or released. They also declined to say whether people who were not targeted were also swept up in the enforcement efforts. Tammy Spicer, an ICE spokeswoman, said national statistics would be published on the agency’s X account.

The New York Times contacted all 25 of the ICE Enforcement and Removal Operations field offices, seeking information about the arrests, but officials either did not respond or declined to share details.

So far, the bulk of the available information about immigrant arrests has come from social media posts by ICE and other federal enforcement agencies. The Times examined accounts from ICE, its sub-agencies and the Drug Enforcement Administration, for individual case information published since increased enforcement began.

All together, they had published details of 59 cases as of Thursday. The White House X account had posted details of 21 additional cases.

The most commonly mentioned offenses were immigration violations, assaults, crimes involving children, and drug and weapons charges. Some of the people arrested were said to have been convicted of a crime, either in the United States or in their home countries. Others were said to have been charged with a crime or suspected of criminal activity.

Mr. Trump pledged throughout his campaign to conduct a mass deportation operation. Since the inauguration, his administration has pushed the message that raids and arrests are meant to take the most serious criminals off the streets.

But Trump officials have said that other immigrants found nearby could also be arrested, in detainments known as “collateral arrests.” Tom Homan, Mr. Trump’s border czar, confirmed that agents made collateral arrests in Chicago last week.

Tom Homan, President Trump’s border czar, said some immigrants without criminal histories had been caught up in immigration sweeps this week.

Reports on the ground appear to coincide with arrest totals. Increased ICE activity has been documented nationwide, with local news media reporting dozens of arrests in Chicago and New York and smaller numbers in other cities. The widespread images and video footage of the new enforcement operations have struck fear into immigrant communities.

Internal ICE data obtained by The Times for a single day last week showed that daily book-ins to ICE facilities were roughly in line with that day’s published arrest total.

But without more complete records, it is not possible to determine whether the small fraction of cases that have been publicized reflect an accurate picture of the overall enforcement effort.

Jason Houser, the ICE chief of staff during the Biden presidency, said he thought that in order to reach a figure on the order of 1,000 daily arrests, hundreds of nonviolent offenders were most likely being apprehended and filling detention space in ICE facilities that are already near capacity.

“ICE should be tackling violent criminals, but the full data will show you that that is not where they are currently focused,” he said.

In at least some cases, agents have detained immigrants who had outstanding deportation orders but no criminal records.

Over the last eight years, ICE arrested around 130,000 people per year, or more than 300 each day. Most years, about 80 percent had a criminal conviction or pending criminal charges, though this category includes misdemeanor charges like traffic violations.

About three-quarters of past ICE arrests were custodial, meaning immigration agents coordinated with local law enforcement to pick up people who were already detained in jails or prisons.

Most of the recently publicized arrests have been at-large arrests in communities, a strategy that requires more time, effort and resources, and that typically accounts for a smaller share of enforcement.