The gang attempted to shoot open the locks on steel gates barring their way to the casino's main safe. "There was lots of shooting, but they couldn't open them," one witness said.
The gunmen ran with their takings to two grey Audi saloon getaway cars and sped away.
Police said a woman casino guest was pulled out of her car and beaten up by the gunmen after she attempted to block their path by parking across the exit road before they escaped. Police said nobody was shot.
Witnesses said they fled in the direction of France and that their cars had French number plates. French and Swiss police were said to have set up a joint investigation unit.
Basel's Grand Casino describes itself as "Las Vegas in the centre of Europe" and attracts high-rollers from across the continent. Many guests stay in the casino's hotel which forms part of the complex.
The casino, which is situated virtually on the Swiss and French borders, is no longer protected by border guards because Switzerland recently joined the Schengen visa-free area in Europe. Police said the gangsters made off with several hundred thousand Swiss francs.
The heist followed an equally spectacular robbery at an international poker tournament in Berlin earlier this month. Four masked men stormed the luxury Grand Hyatt hotel in the city centre and threatened players and staff with pistols and a machete and escaped with £218,000.
Four suspects were arrested or surrendered to police several days after the poker robbery, but the haul has reportedly not been found.
- INDEPENDENT
