The US is stepping up its anti-terrorist efforts in west Africa amid continuing controversy over alleged links between al-Qaeda and the smuggling of Sierra Leonean diamonds through Liberia.
Washington has begun looking more closely at terrorist financing in a region where the US military is increasingly active in efforts to disrupt terrorist networks, according to government officials and a leading Congressman.
A US Congressional panel on the September 11, 2001 terrorist attacks concluded this month there was "no persuasive evidence" that al-Qaeda funded itself through trafficking in diamonds from African states experiencing civil wars. But a US government official covering west Africa told the Financial Times the US authorities had started to examine more deeply alleged financial links between the regime of Charles Taylor, exiled former president of Liberia, and groups such as Hizbollah and al-Qaeda.
"We want to find out the infrastructure," the official said. "Taylor has ties to things other than what's happening in Liberia. We want to find out who and what."
The US military has already launched a programme known as the Pan Sahel initiative to train soldiers in four Muslim- dominated west and central African countries - Mali, Chad, Mauritania and Niger - as part of efforts to prevent terrorists establishing bases there.
The US has allocated an extra legal attaché to west Africa and plans to send support staff to help countries pursue terrorist finance investigations, a counter-terrorism official said. Another initiative will involve working with west African banking authorities to disrupt flows of terrorist funds, some of which could come from the sale of gold and diamonds.
While east Africa is still the principal focus of US anti-terrorism efforts in the continent, west Africa is next on Washington's concerns, the official said. "In coastal west Africa, what we see is the opportunity for terrorist groups to take advantage of exploitable resources," the official said.
A Federal Bureau of Investigation team this year found "pretty definite" evidence of a link between al-Qaeda operatives and the smuggling of Sierra Leonean diamonds, according to the head of the House of Representatives subcommittee that oversees the FBI. In an interview, Frank Wolf, chairman of the House commerce-justice-state and the judiciary appropriations subcommittee, expressed surprise at the September 11 committee's skepticism about the tie and said he would check that it had access to FBI reports on the issue.
Mr Wolf said he asked the FBI team to visit Liberia to investigate concerns about alleged dealings in diamonds by radical Islamic groups groups such as Hizbollah in Lebanon. The investigation established that al-Qaeda operatives visited Liberia to buy diamonds, although Mr. Wolf warned that confidentiality laws prevented him from giving details.
"I can tell you that, to my satisfaction, there is a connection to al-Qaeda," Mr. Wolf said. "Now the question is how much, how extensively, is it still going on?"
Global Witness, a UK-based campaigning group, claimed this month that classified briefings given to congressional members by the FBI's terrorist finance team had confirmed that al-Qaeda operatives visited Liberia and Sierra Leone in order to gain access to the diamond trade.
"The FBI should release an unclassified version of their report as soon as possible," said Alex Yearsley, a Global Witness campaigner.
The FBI declined to comment on the alleged al-Qaeda visits.
The smuggling of "conflict diamonds" from Sierra Leone became a big international issue after the rebel Revolutionary United Front took over the country's main diamond mining areas during the 1991-2002 civil war.
Proceeds from diamond sales helped fund the RUF, which was notorious for chopping off civilians' limbs and abducting children to serve as fighters.
The US government has never officially confirmed claims that al-Qaeda earned about $20m from selling west African diamonds, although officials say a connection with Hizbollah is possible. Diplomats in the region insist a link with al-Qaeda has not been proved despite official investigations of claims first reported in the Washington Post in 2001.
A US intelligence official said it was easy to point to plausible potential financial links between al-Qaeda and west Africa but much harder to find evidence. The official said that Liberia's Mr. Taylor dealt with a Senegalese intermediary who had also met Fazul Abdullah Mohammed, an al-Qaeda operative on the FBI's list of 22 most-wanted terrorists. "We never found anything specific, although when you start looking at links you can make any sort of assumption," the US intelligence official said.
Mr. Mohammed and two other senior al-Qaeda operatives on the most-wanted list - Mohammed Atef and Sheikh Ahmed Salim Swedan - are reportedly under investigation internationally over visits to Liberia between 1999 and 2002. Mr. Atef is believed to have been killed in Afghanistan during the US invasion in 2001. Aafia Siddiqui, believed to be al-Qaeda's only senior female leader, is also reported to be under investigation.
Liberia's Mr. Taylor, who is prohibited from talking to the media under the terms of his exile in Nigeria, has also denied involvement in diamond smuggling and helping terrorist groups. Some observers have suggested the US is reluctant to admit that it failed to spot links between al-Qaeda and Liberia before the September 11 attacks.
The US has close links with Liberia, which was founded in 1847 by freed US slaves, although relations deteriorated after Mr. Taylor's election in 1997.
Mr. Taylor was indicted last year for crimes against humanity by the United Nations-backed Sierra Leone war crimes court. David Crane, the court's chief prosecutor, has on several occasions publicly alleged links between al-Qaeda and west African conflict diamonds.
In an interview, Mr. Crane said he believed there was a terrorist presence in the region but declined to go into details. "There are all sorts of things going on that are outside our mandate and we do not pursue," he said.