NEW YORK — Four families have sued News Corp. and its MySpace social-networking site after their underage daughters were sexually abused by adults they met on the site, lawyers for the families said Thursday.

The law firms, Barry & Loewy LLP of Austin, Texas, and Arnold & Itkin LLP of Houston, said families from New York, Texas, Pennsylvania and South Carolina filed separate suits Wednesday in Los Angeles Superior Court, alleging negligence, recklessness, fraud and negligent misrepresentation by the companies.

"In our view, MySpace waited entirely too long to attempt to institute meaningful security measures that effectively increase the safety of their underage users," said Jason A. Itkin, an Arnold & Itkin lawyer.

MySpace, based in Los Angeles, did not immediately return calls for comment.

Critics including parents, school officials and police have been increasingly warning of online predators at sites like MySpace, where youth-oriented visitors are encouraged to expand their circles of friends using free messaging tools and personal profile pages.

MySpace has responded with added educational efforts and partnerships with law enforcement. The company has also placed restrictions on how adults may contact younger users on MySpace, while developing technologies such as one announced Wednesday to let parents see some aspects of their child's online profile, including the stated age. That tool is expected this summer.

The lawyers who filed the latest lawsuits said the plaintiffs include a 15-year-old girl from Texas who was lured to a meeting, drugged and assaulted in 2006 by an adult MySpace user, who is currently serving a 10-year sentence in Texas after pleading guilty to sexual assault.

The others are a 15-year-old girl from Pennsylvania, a 14-year-old from New York and two South Carolina sisters, ages 14 and 15.

Last June, the mother of a 14-year-old who says she was sexually assaulted by a 19-year-old user sued MySpace and News Corp., seeking $30 million in damages. That lawsuit, filed in a Texas state court, claims the 19-year-old lied about being a senior in high school to gain her trust and phone number.

News Corp. shares hit a new 52-week high of $24.07 in morning trading on the New York Stock Exchange before slipping back to $24.01, up 31 cents.