NEW YORK — NBC News' decision to air some of the video and pictures sent by Virginia Tech shooter Cho Seung-Hui had immediate repercussions Thursday, with family members of victims canceling plans to appear on the "Today" show.

The family members "were very upset" with NBC for airing the images, "Today" host Meredith Vieira said Thursday.

Cho, 23, sent a package filled with rambling, hate-filled video and written messages, and several pictures of him posing with a gun, to NBC News on the morning of his killing spree. It was opened Wednesday and its contents began airing on the network with the "Nightly News."

There were big differences of opinion within NBC News about whether any of the material should be aired at all, "Today" host Matt Lauer said.

"We've made the decision because by showing some of this material, perhaps it will make us understand or answer the question why, why did it happen," he said.

But he said NBC feels strongly that "this is not some kind of video that we need to run in some kind of endless loop," and that NBC would "severely limit" what it airs.

The decision of what the public sees, however, is not entirely in NBC's hands. ABC and CBS began running some of the material almost immediately in their evening news broadcasts Wednesday after recording it off NBC. The images were also shown extensively on cable news networks.

NBC did not show it for several hours at the request of Virginia State Police, who wanted to see it for their investigation.

There was no indication of why Cho chose NBC News for his message, NBC national security reporter Pete Williams said. A Postal Service time stamp shows it was mailed at 9:01 a.m. Monday, during the two hours between his first shooting at a Virginia Tech dorm and his massacre at a classroom building, which he ended by killing himself.