More than 900 people associated with gangs like MS-13 and the Bloods were arrested across the country as part of a five-week U.S. Immigration and Customs Enforcement-led operation, officials announced Monday.

The operation was meant to target gang members involved in criminal activities, such as drug trafficking and human smuggling, and comes at a time that law enforcement officials in the D.C. area have become concerned about an increasing level of violence in the region they associate with the MS-13 gang, reports the Washington Times.

But such federal sweeps often pick up foot soldiers and other low-level gang members, who are ultimately not the ones calling the shots within the criminal enterprises, said gang expert Richard Valdemar, a retired Los Angeles County Sheriff's sergeant who specializes in gang investigations. As a result, he said, they aren't effective tactics in the long term.

"The sweeps are like band aids, they look good on the 5 o'clock news but they have no effect on the actual gangs," Mr. Valdemar said.

More successful are operations that charge gang leadership through Racketeer Influenced and Corrupt Organizations statutes, which can help to disassemble the organizations by ensnaring gang leaders who may not be the ones actually carrying out the most violent crimes, he said.

ICE spokeswoman Sarah Rodriguez said some of those arrested are being charged as part of RICO investigations but she declined to say how many or where the investigations were centered because they are ongoing.