The chips are down for all online gaming firms

Shares in the firm, which is listed on London's Alternative Investment Market (AIM) but operated mainly out of Antigua, were suspended on Monday.

Four of World Gaming's top directors, including chief executive Daniel Moran, have resigned.

US business made up the "overwhelming majority" of revenues, the firm said.

Chief financial officer David Naismith, sales and marketing director Jonathan Moss and non-executive director Michael Cumming have also resigned.

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US lawmakers took the gambling industry by surprise when they agreed sweeping measures criminalising the transfer and handling of proceeds from online gambling earlier this month.

The bill, being signed by President Bush on Friday, effectively makes it illegal to accept bets from US customers.

World Gaming - which traded under sites including sportsbetting.com and betonusa.com - is the first betting firm to collapse as a result of the law.

Other gaming firms, including UK based Partygaming, 888 Holdings and Sportingbet have seen hundreds of millions of pounds wiped off the value of their shares.

But World Gaming was more reliant on the US than its rivals.

Earlier this month it warned that it could be in "technical default of its loan conditions", after seeing its debt level soar to $23m (£12.7m).

Last month, World Gaming's chairman, James Grossman, quit the business as fears grew that top executives at internet gaming firms could be arrested in the US.

The former chairman of Sportingbet and chief executive of Betonsports have both been arrested amid allegations of breaking US gaming laws.

A non-executive director at the firm, Clare Roberts, also resigned.