US Treasury Secretary Steven Mnuchin on Thursday said he has decided against attending a Saudi investment summit later this month following global outrage over the disappearance of Saudi journalist Jamal Khashoggi.

With this he has joined a long list of top US and global leaders, corporate executives and International Monetary Fund and World Bank officials in opting out of the Future Investment Initiative summit in Saudi Arabia. In a tweet, Mnuchin said he met President Donald Trump and Secretary of State Mike Pompeo at the White House.

"We have decided, I will not be participating in the Future Investment Initiative summit in Saudi Arabia," he said.

The decision by Mnuchin comes in the wake of mounting pressure on the Trump administration in the aftermath of the missing Saudi dissident journalist who is feared killed inside Saudi consulate in Istanbul in Turkey early this month.

Saudi Arabia has denied allegations that its officials planned Khashoggi's murder. It has assured the US of a thorough investigation into the matter.

Pompeo on his return from Riyadh and Ankara said the US takes the matter very seriously, but would wait for the investigations to be over and look at the probe report before taking a call on it.

Britain's Trade Minister Liam Fox also pulled out of the conference and French Finance Minister Bruno Le Maire and Dutch Finance Minister Wopke Hoekstra have also cancelled, along with several top business executives, following rising global indignation over the matter.