A dozen US operators joined forces with legal officials from all 50 states to fight nuisance calls, announcing a pact to improve prevention and enforcement efforts.

To help stem the tide of spam calls, cable and wireless providers agreed to monitor their networks for nuisance traffic; offer free call blocking and labelling tools for consumers; and continue the roll out of STIR/SHAKEN call authentication technology.

They also pledged to notify law enforcement and the state attorneys general of suspicious activity; help investigators trace the origins of illegal robocalls; and identify customers participating in spam schemes.

In a statement, North Carolina attorney general Josh Stein said the measures will help state officials “track down the scammers and fraudsters responsible so that we can keep them from preying on people”.

AT&T, Sprint, T-Mobile US, Verizon, US Cellular, Charter Communications, Comcast, Frontier Communications, Consolidated Communications, Bandwidth and Windstream Communications all signed the voluntary agreement.

US residents receive tens of billions of unwanted calls each year, and the pact comes as part of an ongoing effort to damp down the onslaught.

In recent months, the FCC toughened its stance on robocalls, and T-Mobile and AT&T partnered on a cross-network implementation of STIR/SHAKEN earlier this month.