Katie Couric said on Tuesday she is stepping down, as expected, as anchor of the "CBS Evening News," five years after her much-hyped appointment as the first woman to single-handedly host a nightly newscast on a major U.S. television network.

Couric, 54, who moved to CBS News in 2006 after 15 years as co-host of NBC's top-rated morning show, "Today," did not make clear whether she was leaving CBS altogether or when her departure would become effective.

Couric also has been a contributor to the signature CBS weekly news magazine show "60 Minutes" and the "CBS Sunday Morning" broadcast.

The network itself shed little additional light in a brief statement saying, "There's a lot to be proud of during Katie Couric's time at the 'CBS Evening News. CBS News, like Katie herself, is looking forward to the next chapter."

Her five-year contract with the network -- at a salary reported worth $15 million a year -- ends in June, and Couric's career future has been the subject of media reports for weeks.

One source who knew of her plans told Reuters earlier this month that a possible daytime talk show was among several options she was considering.

In an exclusive statement given to People magazine, Couric said she was "looking at a format that will allow me to engage in more multi-dimensional storytelling."

Details of when and where such a show would air had yet to be determined, she said. The New York Times and Los Angeles Times have reported that she has been consulting with Jeff Zucker, her onetime "Today" show producer and former head of NBCUniversal, about her hosting a syndicated show.

Couric was already a well-known celebrity and household from her tenure at "Today" when she was hired by CBS in 2006 to become the first female solo anchor of a major U.S. network evening newscast.

Her arrival was trumpeted by what was believed to be the biggest CBS News promotional blitz since Dan Rather succeeded Walter Cronkite as "Evening News" anchor 25 years earlier. And some critics questioned whether Couric, long the perky darling of morning TV, possessed the journalistic gravitas to succeed.

Network executives hoped her star power would help breathe new life into the newscast in the aftermath of a reporting scandal that shook the network's news division and led to Rather's bitter departure from CBS.

But despite winning a number of prestigious awards and scoring some journalistic coups, including her interviews with Republican vice presidential nominee Sarah Palin in 2008, Couric never managed to lift the "CBS Evening News" out of third place in the ratings war with rivals NBC and ABC.

There was no immediate word from CBS as to who might fill in for Couric at the "Evening News" while the network seeks a permanent replacement