* Phone fraudsters ask companies for money transfers
* Foreign firms in Switzerland targetted
* Employee sent 100,000 francs to account in China
GENEVA, Feb 20 (Reuters) - Fraudsters have been telephoning employees at local branches of international companies in Switzerland pretending to be top executives and asking for urgent money transfers, Swiss police said on Monday.
In the latest case reported by one company last month, the sixth so far known to investigators since 2011, criminals convinced one employee to send 100,000 Swiss francs ($108,300) to an account with a bank in China.
Another, which would have netted the crooks nearly 1 million euros ($1.34 million), was headed off at the last moment according to police in the Vaud canton west of Geneva - apparently when the employee involved became suspicious.
Police declined to say which companies were involved but the light industry and farming canton, whose main city is Lausanne, counts international shipping, tobacco, financial and commodity firms among its businesses.
A police statement said the crooks gather inside information on the business and on senior executives by trawling social websites and hacking internal communications.
They tell their victims, whom they call many times a day, that the money is needed quickly because tax inspections are imminent or because they are buying out another company.
They also tell targeted employee not to report the request to superiors because that would delay the transaction. Often, to add extra pressure, the calls come near the end of the working day on Fridays.
To reinforce their bona fides, the crooks provide numerical codes which have to be repeated at each call. Business sources said victims were threatened that their careers would be damaged if they failed to act promptly.
Vaud police said the calls normally showed French telephone numbers but these were fake as the lines were linked to unidentifiable extensions. Similar cases had been reported affecting French firms in Belgium, the police added.
($1 = 0.9237 Swiss francs)
($1 = 0.7487 euros) (Reporting by Robert Evans; Editing by Jason Webb)