AMC has extended its third-season order for ”The Walking Dead” from 13 episodes to 16, citing its strength domestically and internationally.

The cabler also said that series ”Mad Men” and ”The Killing” will each have two-hour season premieres a week apart, on March 25 and April 1 respectively.

Meanwhile, sister network Sundance Channel renewed ”Iconclasts” for a sixth season and ”All on the Line with Joe Zee” for a third season, and also announced that ”Top of the Lake,” the seven-part miniseries that reunites ”The Piano” director Jane Campion with Oscar-winner Holly Hunter, will begin production in New Zealand on Feb. 7. Elisabeth Moss co-stars.

Speaking at the Television Critics Assn. press tour Saturday in Pasadena, AMC senior veep of programming, production and digital content Joel Stillerman touted AMC’s journey from two original series annually to nine (including three unscripted series) in two years’ time.

However, Stillerman was also contrite about polarized reaction to the loose ends left at the finale of the first season of ”The Killing” last year.

”I want you to know that we learned a lot from your response to season one,” Stillerman said. ”We heard you, and we clearly didn’t sufficiently manage expectations.”

Stillerman said that after considering a number of options, the resolution of the Rosie Larsen murder set up in the series premiere would be revealed at the end of season two (as it was in the program’s Danish forerunner), then added, ”Be nice,” when the assembled media chuckled.

The fifth season of ”Mad Men,” which hasn’t aired a new episode since 2010 because of protracted contract negotiations last year, will launch its first-ever two-hour episode at 9 p.m. before settling into its 10 p.m. slot the following week after the second season of ”The Killing” unfolds with its own two-hour effort. ”Killing” will normally air at 9 p.m.

”The Walking Dead” is returning with a new episode Feb. 12, followed by the premiere of unscripted series ”Comic Book Men,” exec produced by Kevin Smith. ”Walking Dead” has the highest 18-49 rating of any basic cable drama ever and performs well on pay-TV for Fox International Channels’ international markets.

AMC added it will premiere unscripted series ”The Pitch” in season two and ”JJK Security” in the third quarter.

Season five of scripted series ”Breaking Bad” will bow in quarter three, and the next seasons of”The Walking Dead” and ”Hell on Wheels” in quarter four.