Six men have been charged in the United States with conspiring to provide material support and resources to Islamic militants for a series of attacks in the US and overseas.

Five men, all Arab nationals, were indicted in Detroit on charges of acting as a combat cell for Islamic groups waging a self-professed holy war on America and of falsely obtaining passports and other travel documents.

Mr Ujaama is a well-known Muslim activist

A sixth man, an American Muslim, was charged in Seattle with conspiring to provide material support and resources to Osama Bin Laden's al-Qaeda network.

The BBC's Rob Watson says that the charges against Mr Ujaama and the five others are among the most serious levelled in America's hunt for Islamic terror groups after 11 September.

Earnest James Ujaama, who was arrested in July, has strongly denied being linked to terrorist groups.

A federal grand jury charged him with conspiring to aid al-Qaeda while living in London and Seattle.

He was accused of providing training, facilities, computer services, safe houses, and personnel to al-Qaeda with the knowledge that they would be used "to destroy property and murder and maim persons located outside the United States".

Mr Ujaama said in a written statement that he was the victim of a witch hunt, accusing the US authorities of violating his civil rights for "political gain".

Detroit 'sleepers'

Prosecutors in Detroit, Michigan, said at least three of the five suspects there had "operated as a covert underground support unit for terrorist attacks" and were also functioning as a "sleeper" operational combat cell.

The indictment suggested the men - one of whom was charged in absentia - were involved with an Islamic extremist movement known as Salafiyya, which has been linked to al-Qaeda.

America has been a piggy bank for certain terror organisations to the tune of tens of millions of dollars

US law enforcement official

It says they sought to cause economic harm to American businesses, while providing weapons and other support to groups planning terror attacks in Jordan, Turkey and the US.

Four were named as Karim Koubriti, Ahmed Hannan, Youssef Hmimssa and Farouk Ali-Haimoud, while the fifth, who was declared a fugitive, was named simply as Abdella.

The four in custody are believed to originate from Algeria and Morocco and to have been living in the US since 2000.

Three were detained in a raid on a Detroit apartment shortly after 11 September.

The indictment says they possessed plans and sketches of the US Incerlik airbase in Turkey, as well as what appears to be surveillance video of Disneyland in California and other tourist landmarks in Las Vegas.

The men also allegedly checked Detroit's airport for gaps in security

'Terror trove'

Federal agents believe they have uncovered a widespread effort by immigrants to the US supporting anti-Israeli and anti-American militant groups, using credit card thefts, illegal cigarette sales, diverted charitable funds and smuggled cash, officials said.

"The evidence that is being developed suggests that America has been a piggy bank for certain terror organisations to the tune of tens of millions of dollars," said a law enforcement official connected with the case quoted by Associated Press.

Most businesses and charities investigated by US authorities have denied any connections to terrorism, while Arab-American and Muslim activists have accused the authorities of harassment and racial profiling in their investigations.