WASHINGTON (Reuters) - President Barack Obama said on Thursday he has full confidence in Attorney General Eric Holder, who has come under scrutiny after a botched operation to track guns smuggled to Mexican drug cartels.

"I have complete confidence in Attorney General Holder," Obama told a news conference.

"He has been very aggressive in going after gun running and cash transactions that are going to these transnational drug cartels in Mexico," the president said.

The Obama administration has been under scrutiny after revelations that guns were sold to suspected gun traffickers, not properly tracked and ended up at crime scenes in the United States and Mexico.