Former New York City Mayor Rudy Giuliani on Tuesday told FBI special counsel Robert Mueller that President Donald Trump and his advisers remain resistant to an interview, though he did not rule one out, according to officials who spoke with The Washington Post.

Giuliani, a former federal prosecutor and longtime Trump ally, last Thursday said he was joining Trump's legal team to try to end Mueller's probe "for the good of the country."

During his meeting with Mueller, he pressed for clarity on when the probe would end and said the president was "extremely opposed" to granting an interview. Mueller told Giuliani he wanted a chance to ask Trump questions about some of his actions early on in his presidency, and an interview was essential to understanding the president's intent.

Trump in early January said he was "looking forward" to an interview with Mueller, and his legal team started preparing him for the possibility of one in early April. He has backed off since the announcement his personal lawyer Michael Cohen was being investigated for potential bank fraud and campaign-finance violations.

Mueller in early April informed Trump's attorneys the president remains under investigation, but was not a criminal target. The special counsel also said he was preparing a report about potential obstruction of justice and Trump's actions while in office.