LUXEMBOURG, June 7 (UPI) -- A U.S. Treasury official has urged Europe to dig deeper to find and block terrorist financing, while some European authorities say they need more proof to identify terrorist money.

Jimmy Gurule, undersecretary for enforcement, said $116 million in suspected terrorist assets linked to Osama bin Laden´s network has been blocked worldwide since last September -- about $82 million of it outside the United States. The European Commission says an estimated $94 million in assets belonging to persons or entities sponsoring terrorist acts have been frozen in the European Union since Sept. 11th, when terrorists attacked the World Trade Center in New York and the Pentagon just outside of Washington.

But Gurule said the war against terrorist financing is long-term, and more needs to be done. In an interview, he argued that while obvious targets have been achieved, more individuals and groups have to be identified.

"I think that what we´ve seen certainly is that we have kind-of taken care of, with respect to designations, the so-called low-hanging fruit. I mean the obvious targets, terrorist organizations, terrorist financiers have been designated. Now we´re getting down to the tougher names where there may be disagreement as to whether or not these individuals are supporting terror."

Gurule spoke in Luxembourg Thursday, one of Europe´s banking capitals. Earlier this week he took a similar message to European Union officials in Brussels and later to Switzerland, another country heavily into financial transactions. Gurule praised Luxembourg for its support for the war against terrorist financing and said Washington is looking for ways to enhance that cooperation.

Luxembourg Treasury and Justice Minister Luc Frieden noted that his small nation already has much stricter legislation on money laundering issues than other countries, because Luxembourg is a major European financial center. He said prevention mechanisms like "know your customer" have been in place for a long time.

Frieden also said certain accounts were freed for use in recent weeks because there was no proof to justify holding the funds further.

Other nations, including Sweden and Switzerland, have said their laws require proof for authorities to continue holding money of potentially suspicious accounts. Financial prosecutions are very complicated, and some European authorities say that information released by Washington is not enough to verify terrorist links.

They say Washington withholds information to avoid compromising intelligence sources or operations. Gurule acknowledged the problem.

"This is a very complicated business that we´re involved in. In many instances the information that we have is classified information. It´s classified by our intelligence agency ... and because of these competing concerns it may be that we are not able to disclose that classified information with our allies."

In Sweden, The United States listed Al-Barakaat, a Somali-owned money transfer service, as a backer of Osama bin Laden´s terror network. Swedish officials asked for more evidence on three Swedish-Somalis accused in the case.

Gurule said the United States is reviewing cases of two of the individuals and is close to a decision on whether they will be taken off the terrorism financing list. The Somalis have also appealed to the European Court of Justice.

European countries accepted U.S. lists of suspected terrorist financiers following the Sept. 11th attacks, but difficulties later arose. The reliability of the lists has been questioned because some Arabic names were misspelled, some people included turned out to be dead, and basic details like place and date of birth were sometimes missing.

Gurule admitted shortcomings, but said information is improving.

"In some cases we´re not able to uncover and determine and provide this type of detailed information," Gurule said. "I think we´re getting better. I think that as a result of a better sharing of information between the intelligence community and federal law enforcement community of the United States, it is making it easier for us to collect this information and share it with our allies abroad." (Copyright © 2002 United Press International 06/07/02)