WASHINGTON Days after President Donald Trump attacked the FBI , the man he appointed to head the nations premier law enforcement agency told members of Congress there is no finer institution than the FBI.

FBI Director Chris Wray, who took over the bureau in August, appeared before the House Judiciary Committee for an oversight hearing on Thursday. In his opening statement, he said there were no finer people than the men and women who work at the FBI, calling them its very beating heart.

Wrays remarks followed Trumps attack on the FBI in a tweet on Sunday, when the president wrote that the bureaus reputation is in Tatters - worst in History!

Under questioning from House Judiciary Ranking Member Jerrold Nadler (D-N.Y.), Wray responded directly to Trumps tweet, saying there was no shortage of opinions out there. He then described the FBI he knows: a bureau full of tens of thousands of brave men and women working hard to keep Americans safe from harm from threats like gang violence, child predators and terrorists. He spoke of being inspired by the recent graduates of FBI academy in Quantico, and of the response teams the FBI sends into harms way.

Now, do we make mistakes? You bet we make mistakes, just like everybody who is human makes mistakes, Wray testified. And when we make mistakes, there are independent processes like that of the outside, independent inspector general that will drive and dive deep into the facts surrounding those mistakes. And when that independent fact-finding is complete, will we hold our folks accountable if thats appropriate.

Wray also said Trump never asked him to sidestep the chain of command or to pledge his loyalty to the president.

Later, Wray said FBI agents are big boys and girls who understand theyll take criticism from all corners, and can handle it.

The FBI director this week sent a message to bureau employees that seemed to respond to the presidents tweets, but he hadnt made a public comment about the attack until Thursday.

Trump has lashed out at the FBI as the special counsel investigation run by former FBI Director Bob Mueller has led to indictments or guilty pleas of four Trump campaign officials, including the presidents former national security adviser .