NEW YORK - NBC News said Tuesday it has reprimanded the employee responsible for mistakenly flashing a picture of Osama bin Laden on MSNBC as Chris Matthews talked about Barack Obama.

"This mistake was inexcusable," MSNBC spokesman Jeremy Gaines said.

It happened during the opening of "Hardball" Monday evening. Matthews was previewing a story on the controversy over Obama's use of another politician's words, and a picture of bin Laden briefly flashed on the screen beside him with the headline "Words About Words."

The Obama campaign immediately called NBC to complain, and Matthews apologized on the air a few minutes later. When "Hardball" was rerun later that night, a picture of Obama replaced the picture of the terrorist leader.

The mistake was made by someone in the network's graphics department whom MSNBC would not identify. The network did not explain exactly how the mistake was made nor detail the punishment for the employee.