US Attorney Mary Jo White reads the charges

The attacks in Kenya and Tanzania in early August left 224 people dead and injured thousands.

Mr bin Laden is believed to be in Afghanistan, and an international warrant was earlier issued for his arrest in connection with a general campaign against American interests.

US ambassador Prudence Bushnell was wounded in the Nairobi blast

A federal grand jury indicted the millionaire after hearing evidence from American prosecutors.

Their decision is a first step towards putting Mr bin Laden on trial in the United States.

The $5m reward is more than twice the $2m limit the US has previously offered in what it calls terrorist cases.

The limit was raised as a result of legislation passed recently by the US Congress.

'A pretty big guy'

FBI official Louis Schirilo: "We will identify, locate and prosecute"

A similar reward is also expected to be offered for the arrest of another suspect, identified as Mohammed Atef.

A US official said: "There is going to be an announcement of a reward offer of up to $5 million for each of them.

"This is the first opportunity we've had to come out and say that the amount we can offer has increased, and we're doing it for a pretty big guy."

Federal prosecutors have been building a case against Mr bin Laden and his al Queda organisation since at least 1995.

Their efforts expanded after the 7 August bombings of the US embassies in Nairobi and Dar-es-Salaam.

Following the attacks, the US carried out military strikes against targets in Afghanistan and Sudan, which it alleged were connected with Mr bin Laden.

The strikes were denounced in the Arab and Islamic worlds and Mr bin Laden renewed his threat to wage a holy war against the US.