U.S. President Barack Obama on Thursday tried to push back on scandals and controversies that are surrounding his administration, saying he had no prior knowledge of the Internal Revenue Service's (IRS) targeting of conservative groups, and he has full confidence in Eric Holder, his embattled attorney general.

Obama made the comments during a joint press conference with visiting Turkish Prime Minister Recep Tayyip Erdogan. On the IRS, he said though the White House counsel's office was informed of a probe to the federal tax agency in April, he only learned about its practice of targeting of conservative groups through media reports last Friday.

"I'm looking forward to working with Congress to fully investigate what happened, make sure that it doesn't happen again, " said Obama, adding "I think we're going to be able to fix it."

Obama announced on Wednesday that Treasury Secretary Jack Lew had asked for and received the resignation of IRS chief Steven Miller.

At the same press conference, Obama also defended Holder, whose Justice Department was involved in controversial seizure of a wide swath of phone records of the Associated Press in a leak probe.

"I have complete confidence in Eric Holder as attorney general. He's an outstanding attorney general and does his job with integrity," said Obama, adding he makes "no apologies" on conducting leak probes, but he also touted his administration's efforts in pushing for the media shield laws, which would protect journalists from being compelled to testify about their confidential sources. Endi