NEW YORK (Reuters) - Two of the media industry’s highest profile executives said on Friday they would leave NBC Universal and CNN, victims of a ratings war and chaotic shifts in the business.

NBC Universal Chief Executive Jeff Zucker will step down once Comcast Corp takes control of the company, expected by the end of this year.

CNN’s U.S. network chief, Jonathan Klein, left the pioneering cable network on Friday.

Zucker had rocketed up the corporate ladder but recently encountered several high-profile setbacks, including unsuccessfully moving Jay Leno to prime-time and then having to move him back to late night.

The announcement of his departure came about an hour after Time Warner Inc’s CNN said Klein had been replaced.

Both Zucker and Klein had been under a harsh spotlight for months as their networks lost viewers in the increasingly vicious battle to win prime-time evening slots.

These management shake-ups follow the resignation earlier this month of ABC News President David Westin after 13 years.

Zucker, 45, said in an interview with Reuters that he wished he had been able to fix the NBC broadcast network, which has had steep ratings declines and few genuine hits in the last four years.

“I came to grips with the right time for me to move on and at the same time Comcast said to me they wanted me to move on, so we kind of got to the same place,” Zucker said.

“My biggest regret is that we haven’t had more success in turning round NBC Entertainment,” he said. “Other than that, I feel very confident about what we’ve done with the company.”

Zucker said he would leave the job once Comcast had completed its deal to take control of NBC Universal from current owner General Electric Co. The deal is expected to close by the end of 2010.

Many media watchers had anticipated that Zucker, who became chief executive at NBC Universal in 2007, would leave NBC after the Comcast deal was announced in December.

Steve Burke, Comcast’s chief operating officer, is overseeing preparations for integrating NBC Universal, and analysts have he could end up running the business once the deal closes.

Other media executives who could be candidates for senior jobs at NBC Universal include former News Corp Chief Operating Officer Peter Chernin and Tom Freston, one-time boss at Viacom Inc.

HITS AND MISSES

Zucker had no shortage of success at NBC Universal. He joined the company straight out of college in 1986, and worked his way through the ranks until taking over as chief executive in 2007.

He is credited with building up NBC Universal’s strong cable networks, which now account for roughly 60 percent of NBC Universal’s revenue. The company also owns a movie studio and theme parks.

In recent years, however, he has found himself at the center of controversies like his handling of NBC’s signature late-night program, “The Tonight Show.” Comedian Conan O’Brien took over the show from Jay Leno last year as part of a long-planned succession. But O’Brien quit after the network asked for Leno to return as a lead-in.

Industry watchers also questioned Zucker’s decision to make Ben Silverman head of NBC Entertainment in 2007, which was soon followed by ratings declines. Silverman left in 2009.

NO JOY FOR KLEIN AT CNN

Klein, who spent six years as president of CNN US, was pushed out amid a restructuring of CNN’s prime-time program lineup.

“I feel disappointed and wistful about leaving a lot of people I really like,” Klein told Reuters in an interview. “CNN was pursuing a structural change that didn’t leave room for me.”

Klein said he was surprised by the timing of his departure because CNN is about to roll out new prime-time shows with presenters he brought to the network, including British journalist Piers Morgan, former New York Governor Eliot Spitzer and columnist Kathleen Parker.

“I would have thought the reckoning would come after the shows had launched, and we could tell something about the quality and the performance,” he said.

Klein has been criticized at CNN, which has been badly trailing News Corp’s Fox News. In the prime-time evening slot, which is largely seen as the ‘face’ of any cable network, CNN has dropped to fourth place on some nights behind Fox News, MSNBC and CNN’s sister network HLN.

Ken Jautz, a longtime CNN executive who most recently oversaw the HLN network, will replace him.