Updated

GRAND ISLAND, Neb. -- Federal agents have made a series of gang-related drugs and weapons arrests in the central Nebraska city of Grand Island.

An FBI advisory issued Thursday says numerous people were arrested early Thursday as part of a multi-agency operation involving 120 federal and local law enforcement officers.

Federal charges include narcotics trafficking and firearms violations. State charges have also been filed, including those under a new Nebraska law intended to combat gang recruitment.

The FBI and federal immigration officials were to hold a news conference Thursday afternoon to release more details of the arrests.

It was unclear from the advisory how many people had been arrested.

The city of about 50,000 has seen an increase in gang-related violence in recent years. In January, a 15-year-old student was shot at a Grand Island home in what was believed to have been a gang-related altercation.

Rumors of gang-retaliation following the shooting swept through the city, prompting police to station officers carrying AR-15 assault rifles at Grand Island High School entrances to reassure students and parents.

Earlier this year, Hall County Attorney Mark Young estimated there were fewer than 100 gang members in the city.