Tom Cruise just filed a $50 million lawsuit against Life & Style and In Touch magazines, claiming the mags defamed him by reporting he had abandoned 6-year-old Suri.

In the lawsuit, filed in L.A. federal court, Tom takes issue with the July 30th cover of Life & Style, which reads, "SURI IN TEARS, ABANDONED BY HER DAD" -- as well as the October 1st cover of In Touch, which shows a picture of Suri above the headline, "ABANDONED BY DADDY."

According to the suit, Tom claims the mags' headlines are FALSE -- insisting, he "loves his daughter dearly and would never abandon her."