Saudi Arabia and the United States are to create a joint task force aimed at combating the funding of extremist groups in the country, US reports have said.
Saudi Arabia cracked down on militants after the deadly May bombings
Agents from the US Federal Bureau of Investigation (FBI) and the Internal Revenue Service (IRS) are due to fly to Riyadh this week to begin setting up the force, the Washington Post newspaper reported.
The operation will focus on gathering information from bank accounts, computer records and other financial data to track and then cut off the money flow, senior officials from both governments told the paper.
"[The task force] represents kindled, renewed fervour on the part of the Saudis to get to the bottom of terrorism within their own peninsula," David Aufhauser, general counsel of the US Treasury Department, told Associated Press news agency.
The task force's success would also be an effective test of whether the Saudi Government was serious in halting extremist activity within its borders, added Mr Aufhauser - who heads US efforts to combat terrorism financing.
Relations between the two nations were further strained in July after the US refused to publish a classified section of a Congressional report into the 11 September 2001 attacks.
Many suspected that the pages would have detailed allegations about Saudi support and involvement in the plot.
Fifteen of the 19 hijackers who crashed planes into the World Trade Center towers, the Pentagon and a field in Pennsylvania were from the kingdom.
Saudi Arabia angrily condemned the decision, denying any such involvement and arguing that it could not defend itself adequately when the information was not public.
It already faces severe pressure from the US to crack down on Islamic extremists within the kingdom since the bombings in Riyadh in May this year which left more than 30 people dead.
Scores of militants have been arrested and several killed in gun battles with Saudi security forces in the months since the attacks.