Washington - Donald Trump's nominee to lead the FBI pledged on Wednesday to insulate the agency from outside interference, amid a probe into Russian election interference that could threaten the president and his inner circle."If I am given the honour of leading this agency, I will never allow the FBI's work to be driven by anything other than the facts, the law, and the impartial pursuit of justice. Period," Christopher Wray told a Senate Judiciary Committee hearing on his nomination."There is only one right way to do this job, and that is with strict independence, by the book, playing it straight, faithful to the constitution, faithful to our laws, faithful to the best practices of the institution, without fear, without favouritism, and certainly without regard to any partisan political influence," he said.Trump fired the respected director of the Federal Bureau of Investigation James Comey in May, expressing frustration about the ongoing investigation into whether his presidential campaign colluded with an alleged Russian effort to tilt the election in his favor.That raised allegations of obstruction of justice against the president and led to the appointment of an independent prosecutor, Robert Mueller, another former FBI chief, to oversee the Russia probe.Senator Dianne Feinstein, the top Democrat on the judiciary panel, told Wray he must be committed to pursuing any investigation to the end no matter who is implicated."The FBI director does not serve the president," Feinstein told the hearing."He serves the constitution, the law and the American people. As such, the director of the FBI must be a leader who has the integrity and strength that will enable him to withstand any attempts at political interference."