WASHINGTON, June 4 (Xinhua) -- U.S. President Donald Trump said on Monday that he could pardon himself, sparking controversy as no president has ever pardoned themselves in U.S. history.

"As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong?" Trump tweeted, adding that he has been the victim of a lengthy "witch hunt."

It was not immediately clear why Trump chose to bring up the matter of pardoning himself.

White House Press Secretary Sarah Sanders later tried to downplay Trump's tweet by insisting that there is no need for her boss to pardon himself because there is no wrongdoing.

"Thankfully, the president hasn't done anything wrong and wouldn't have any need for a pardon," Sanders said.

"Certainly no one is above the law," Sanders later added after being pressed by journalists.

Despite the White House' effort to downplay the issue, many of Trump's opponents and some Republican allies frowned upon the remark.

Senate Judiciary Committee Chairman Chuck Grassley, a Republican, said: "If I were president of the United States and I had a lawyer that told me I could pardon myself, I think I would hire a new lawyer."

According to the U.S. constitution, the U.S. president "shall have power to grant reprieves and pardons for offences against the United States, except in cases of impeachment."

Legal experts and politicians are struggling to reach a consensus on the issue, with some arguing the wording does not ban the president from pardoning himself, while others say allowing presidents to forgive themselves would give them power to operate above the law.

Despite the differences, both sides agree that it is in Trump's interest not to become the first president to pardon himself.