A $3m (£1.9m) reward is being offered for information leading to the arrest of a man US authorities have called one of the worlds most prolific cyber hackers.

Evgeniy Bogachev was indicted in Pittsburgh, Pennsylvania, last year on charges including bank fraud and conspiracy.

He is believed to be in Russia, and pictures of him have been plastered on "Wanted" signs distributed by the FBI.

Bogachev is accused of acting as the ringleader for a large hacking operation that installed malicious software on victims computers in order to gain bank account numbers, passwords and other sensitive information.

The computer attack network, called GameOver Zeus, allegedly stole more than $100m (£64m) from online bank accounts.

Bogachev is said to be the leader of a gang accused of stealing over $100m

Bogachev also faces federal bank fraud conspiracy charges in Omaha, Nebraska, relating to his alleged involvement in an earlier version of Zeus malware known as "Jabber Zeus".

Despite the reward, which is the highest bounty the US has ever offered in a cyber case, arresting overseas hackers is difficult for US authorities, particularly in countries like Russia where there is no extradition treaty.

Joseph Demarest, head of the FBIs cyber crime division, said that Russias internal security agency, the FSB, had recently expressed a tentative interest in working with the US on cyber crimes.

However, he did not link the offer to the Bogachev case.