Updated

MSNBC host Keith Olbermann was put on indefinite suspension Friday after bosses at the cable news network learned that he had donated to three Democratic candidates, including one who had appeared on his show on the same day, in violation of the network's rules.

"I became aware of Keith's political contributions late last night. Mindful of NBC News policy and standards, I have suspended him indefinitely without pay," Phil Griffin, president of MSNBC, said in a statement.

The three candidates who received the maximum legal amount of $2,400 are Reps. Raul Grijalva and Gabrielle Giffords, both of Arizona and both who won tough re-election bids. Kentucky Senate candidate Jack Conway was the third recipient. He lost to Republican Rand Paul.

The donations were made on Oct. 28, the same day Grijalva appeared on the MSNBC show "Countdown With Keith Olbermann."

Politico, which was first to report the contributions, published Olbermann's confirmation of the donations.

"I did not privately or publicly encourage anyone else to donate to these campaigns nor to any others in this election or any previous ones, nor have I previously donated to any political campaign at any level," Olbermann said in a statement to the newspaper.

NBC News prohibits its employees from working on, or donating to, political campaigns unless a special exception is granted by the news division president -- effectively a ban. Olbermann's bosses did not find out about the donations until after they were made.

Olbermann was a co-anchor of MSNBC's election coverage this week. The network's performance drew some criticism, particularly with Chris Matthews' contentious interviews with Republican Bachmann and Marsha Blackburn.

Olbermann was seen laughing following Matthews' conversation with Bachmann. Matthews had criticized the congresswoman for failing to answer his questions.

Chris Hayes will fill in for Olbermann on Friday's program, the network said.

The Associated Press contributed to this report.