JAKARTA, Oct 29 (Reuters) - Indonesian police said on Thursday they had detained two top anti-graft officials, despite mounting concerns over the authorities' handling of the controversial case.

The powerful Corruption Eradication Commission, or KPK, has been at the forefront of Indonesia's efforts to tackle endemic graft and its success in investigating and charging corrupt government and other officials has made it many enemies.

Chandra Hamzah and Bibit Samad Riyanto, two of the four deputy chiefs at the KPK, are under investigation for suspected corruption and abuse of power. Both deny the allegations.

Local media reported this week the two men, who were recently removed from their posts, may have been framed by law enforcement authorities.

The media reports are based on what were said to be transcripts of recorded conversations between several individuals, including a businessman, a former official from the attorney general's office, and a police investigator, in which they appeared to plan the framing of the two KPK officials.

According to the Jakarta Post, Deputy Attorney General Abdul Hakim Ritonga, one of the officials named in the transcript, urged the police to drop the case against Hamzah and Riyanto. Ritonga said he was the victim of slander.

Instead of dropping the case, the police announced on Thursday they would detain the two men indefinitely.

"Starting from today, we will exercise our right to detain the two suspects," said Dikdik Arief Mansur, the national deputy chief of detectives, saying that evidence implicating the pair would be presented in court.