Credit: Splash News.

As Tom Cruise marks his 50th birthday today, Katie Holmes is further distancing herself from her soon-to-be ex-husband.

A source familiar with Holmes' security detail confirmed to ABC News that Holmes has fired the security team Cruise employed for her for years. Another source told ABC News that one of the main reasons she filed for divorce was Cruise's loyalty to Scientology.

Representatives for Cruise and Holmes have thus far declined to comment on whether Scientology played a part in their split.

Meanwhile, according to Us Weekly, Cruise left Iceland last night, where he was filming the movie "Oblivion," to head back to California.

Holmes is currently in New York, where she filmed an appearance on "Project Runway: All Stars" Monday and filed for divorce Thursday. Photographers captured her wearing a tight-lipped smile as she walked through the city. Notably absent: her wedding ring.