Robocalls have emerged as the single largest source of complaints to authorities.

In a significant development, the attorneys general from 50 U.S. states as well as from the District of Columbia stated, they are joining forces with major U.S. telecommunications providers, including Comcast Corp, AT&T Inc, T-Mobile Us Inc, Verizon Communications Inc, and Sprint Corp to crack down on unwanted robocalls.

The state AGs and companies are unveiling non-binding “anti-robocall principles.”

These companies have all agreed to take measure to reduce unwanted calls as well as collaborate with the state attorney generals over “recognized scams and trends in illegal robocalling”; they will also update states on “potential additional solutions for combating illegal robocall.”

Incidentally, robocalls have emerged as the single largest source of complaints to the Federal Trade Commission, Federal Communications Commission, and to many state attorneys general offices.

In recent months, the U.S. Congress has been working on legislation to crack down on unwanted calls.