The US federal authorities do not have an understanding of how terrorists move their financial assets and are struggling to prevent flow of money to terror groups, a report has said.

The Internal Revenue Service has not developed a formal plan for sharing financial information with state authorities about charities under investigation, the report by the General Accounting Office, the investigative arm of Congress, to be made public Sunday, said.

The Treasury and Justice departments have fallen nearly a year behind in developing a plan for attacking money laundering and issues like terrorists' use of black-market gems and gold, The New York Times quoted the report as saying.

It said some agencies have failed to make prevention of terror financing a high priority or have set unrealistic goals for overhauling their tactics.

The findings, the paper said, come at a time when some government officials and lawmakers say they have grown increasingly concerned about weaknesses in the government's ability to track terror financing.

Law enforcement officials also acknowledge that gaining a clear understanding of how terrorists move their money has proven far more difficult than many anticipated and that recent attacks in Saudi Arabia, Turkey and elsewhere point to terror groups with continued access to significant resources, the paper said.

Justice Department officials, the paper said, acknowledged to investigators that the FBI "does not systematically collect and analyse" information on financing used by terrorists. Such schemes have involved filtering money through charities or laundering it by selling diamonds and gold, or even cigarettes and household appliances on the black market.

The investigation "is a real eye opener," said Senator Richard J Durbin, a Democrat from Illinois, who requested the study along with Iowa Republican Senator Charles E Grassley.

"This is an indication that we were naive to believe that all of our attention had this problem under control," Senator Durbin said. "I don't think we're close, and this report says that terrorists are going to continue to have resources at their disposal."

Several current and former government officials were quoted as saying that they believed that federal agencies have made strong progress in the last two years in attacking terrorist financing, and have committed more agents and greater coordination to the problem.

"There have been real and material advances in the war on terrorist financing since 9/11," said David Aufhauser, the Treasury Department's former general counsel, who left the government in October after working extensively on the
terrorist financing issue. "It's now part of the international agenda and has to be part of the international agenda in order
to be effective."