WASHINGTON (CBSDC) — Eric Holder feels his biggest failure as attorney general under President Barack Obama was the inability to pass federal gun control laws following the deadly Sandy Hook Elementary school shooting.

Holder made the revelation to CNN on Monday.

“I think the inability to pass reasonable gun safety laws after the Newtown massacre is for me something that I take personally as a failure, and something I think we as a society should take as a failure,” Holder told CNN.

The attorney general was referring to the deadly school shooting in Newtown, Conn., where Adam Lanza gunned down 26 people, including 20 children, at Sandy Hook Elementary School in 2012.

Following the shooting, the Obama administration pushed for stricter gun control laws. A universal background check bipartisan bill failed in the Senate in April 2013.

Holder also said in the interview with CNN that he was disappointed with former Defense Secretary Leon Panetta’s criticism of Obama in a recent book.

“I really disagree with his characterization of the president. The president is a deliberate person in an appropriate way, but he is also resolute once he makes up his mind,” Holder explained to CNN. “So I think that what Leon said in the book is unfortunate. And frankly, I don’t think it’s something a former Cabinet member should do while the president you served is still in office. That’s not something I would even consider doing.”

Holder announced his resignation last month as attorney general after serving for six years. The first African-American attorney general will stay on until his successor is confirmed.