UPDATE 1-Iran: Riyadh would not have murdered Khashoggi without US protection

President Donald Trump said on Tuesday Saudi authorities staged the "worst cover-up ever" in the killing of Khashoggi in Turkey this month, as the United States vowed to revoke the visas of some of those believed to be responsible.

Iranian President Hassan Rouhani said on Wednesday that Saudi Arabia would not have murdered prominent journalist Jamal Khashoggi without American protection, according to the Islamic Republic News Agency (IRNA).

President Donald Trump said on Tuesday Saudi authorities staged the "worst cover-up ever" in the killing of Khashoggi in Turkey this month, as the United States vowed to revoke the visas of some of those believed to be responsible.

"No one would imagine that in today's world and a new century that we would witness such an organised murder and a system would plan out such a heinous murder," Rouhani said, according to IRNA.

"I don't think that a country would dare commit such a crime without the protection of America."

Iran and Saudi Arabia are regional rivals and have supported opposing sides in the conflicts in Syria and Yemen and different political factions in Iraq and Lebanon.

U.S. protection has allowed Saudi Arabia to carry out bombings against civilians in Yemen's war, Rouhani said, according to IRNA.

"If there was no American protection, would the people of Yemen still have faced the same brutal bombing?" Rouhani said.

Rouhani also called on Turkey's government to conduct an impartial investigation into Khashoggi's "unprecedented" murder.