The recent surge of federal immigration enforcement in Massachusetts known as Operation Patriot 2.0 resulted in just over 1,400 arrests, officials said Thursday.

Of the 1,406 undocumented immigrants arrested over the Sept. 4-30 operation, over 600, or less than half, have been convicted of or charged with significant crimes, according to Thursday’s announcement from U.S. Immigration Customs and Enforcement. They said that 277 of those arrested were in the country despite being ordered removed by an immigration judge.

The first ICE surge in Massachusetts known as Operation Patriot, in May, netted 1,461 arrests, of which 790 involved a person with “significant criminality,” officials said at the time.

It wasn’t immediately clear how many federal agents were taking part in Operation Patriot 2.0, or what Massachusetts communities the operation was being conducted in.

Operation Patriot 2.0 involved several federal agencies beyond ICE, including the FBI, U.S. Customs and Boarder Protection and U.S. Marshals Service, officials said. Six people arrested were allegedly part of prominent transnational gangs like MS-13 and Tren de Aragua; others arrested, according to the announcement, include people convicted of second-degree murder, child rape, kidnapping and drug charges.

“Every illegal alien we arrested during the operation was breaking U.S. immigration law, and hundreds were violent criminals who should never have been allowed to roam freely in our communities,” acting ICE Director Todd Lyons said in a statement. “Local law enforcement agencies released them instead of handing them over to us in a secure environment, and this puts neighborhoods, law enforcement officers and illegal aliens at risk. Local politicians are responsible for protecting their constituents, so they need to step up and end irresponsible sanctuary policies.”

Gov. Maura Healey has long insisted that Massachusetts is not a sanctuary state and emphasized her experience prosecuting , while Boston Mayor Michelle Wu has said the city follows laws, including its Trust Act, which limits city workers’ involvement with federal civil immigration enforcement.

Both have also pointed to Massachusetts’ and Boston’s records on public safety.