WASHINGTON (Reuters) - The director of the Federal Bureau of Investigation defended his  employees on Thursday against a growing chorus of accusations by Republicans, including President Donald Trump, that its agents were allowing political bias to seep into their investigations. In testimony before the House of Representatives Judiciary Committee, Christopher Wray said he believed the reputation of the FBI was not, as Trump recently wrote on Twitter, “in tatters.” “The agents, analysts and staff of the FBI are big boys and girls. We understand we will take criticism from all corners,” Wray said.  “My experience has been that our reputation is quite good.” Republicans had in recent weeks stepped up criticism of the FBI and Special Counsel Robert Mueller, who is investigating whether Trump campaign aides had colluded with Russia to influence the 2016 U.S. presidential election. The move is widely seen as a tactic to undermine Mueller’s investigation, which has so far led to criminal charges against four people from Trump’s inner circle. It comes as Republicans prepare to head into a potentially challenging midterm 2018 congressional election cycle. Republicans have sought to re-litigate questions relating to the FBI’s handling of an investigation into Hillary Clinton’s use of a private email server, and questioned whether Justice Department officials gave her preferential treatment in their decision not to charge her with a crime. They have criticized former FBI Director James Comey for publicly announcing a decision not to refer Clinton for prosecution and asked whether the decision-making was politically tainted.  Wray took over the helm of the FBI after Trump abruptly fired Comey earlier this year.     Most recently, Republicans got fresh ammunition against Mueller and the FBI, after media reports said FBI agent Peter Strzok was removed from the Russia probe because he had exchanged private text messages that disparaged Trump and supported Clinton. Strzok was involved in both the Clinton email and Russia investigations.  Wray acknowledged Thursday that Strzok was removed from Mueller’s investigation, but said he was reassigned, not disciplined. “We cannot afford for the FBI - which has traditionally been dubbed the premier law enforcement agency in the world - to become tainted by politicization or the perception of a lack of even-handedness,” Committee Chairman Bob Goodlatte said.  Wray repeatedly refused to weigh in on how his predecessor handled the Clinton matter, and deferred to Justice Department Inspector General Michael Horowitz, who is conducting a wide-ranging review into the topic. Horowitz recently told lawmakers he expects his review to be complete by late winter or early spring. “When those findings come to me, I will take appropriate action if necessary,” Wray said. Democrats, meanwhile, urged Wray to stand up against bullying by the president. “Your job requires you to have the courage to stand up to the president, Mr. Director,” said the committee’s Ranking Democrat Jerrold Nadler. “There are real consequences for allowing the President to continue unchecked in this manner.” 