Federal agents inspect bullet impacts at a crime scene in the town of Ocotlan, Jalisco March 20, 2015. Ten people were killed in a gunfight in western Mexico Friday when suspected gang members ambushed a police convoy, the government said on Friday. Five members of Mexico's militarised police, or gendarmerie, were killed in the shootout in Ocotlan, Jalisco state, and eight others were wounded, the National Security Commission said in a statement. REUTERS/Alejandro Acosta

(Reuters) - Nearly 1,000 gang members and associates from 239 different gangs were arrested across the United States in an operation headed by Immigration and Customs Enforcement agents, the agency said on Wednesday.

The sweep, dubbed "Project Wildfire" and led by ICE's Homeland Security Investigations unit, was aimed at criminal gangs that work across international borders, ICE said in a statement.

During the operation, 976 gang members and associates were arrested in 282 cities. Most of those arrested were U.S. citizens, but 199 foreign nationals were also arrested, from 18 countries in South and Central America, Asia, Africa, Europe and the Caribbean, the statement said.

Two hundred and thirty-one other people were arrested for federal or state criminal violations and immigration violations, it said. The operation ran from Feb. 23 to March 31.

Of the 976 gang members or associates, 913 were charged with criminal offenses and 63 were arrested administratively for immigration violations.

Most of those arrested were affiliated with gangs including the Sureños, Norteños, Bloods and Crips, the statement said.

HSI agents also seized 82 firearms, drugs, U.S. currency, counterfeit merchandise, and vehicles, the statement said.