Worldcom has become the latest US telecoms firm to come under closer scrutiny from stock market regulators.

Worldcom, the US' second biggest long-distance phone company, said on Tuesday that the Securities and Exchange Commission last week asked to inspect some of its financial records.

Analysts said the documents in question relate to sales commissions and loans advanced to some executives, but do not concern Worldcom's method of revenue recognition.

The company said its accounting practices are in order, and stressed that it plans to cooperate fully with the SEC 's request.

Shares slide

But the news unnerved investors, pushing Worldcom shares down 11% to $7.99 at about 1700 GMT.

Worldcom, hit hard by weaker profits and concerns over its heavy debts, has already seen its share price fall steeply in recent months.

The company last year announced a series lay-offs in an attempt to cut costs.

Probe widens

Worldcom is the third major US telecommunications company after Global Crossing and Qwest Communications to have its accounts checked by the SEC.

The inspections come against a background of heightened investor sensitivity to opaque corporate bookkeeping in the wake of the shock collapse of former energy trading giant Enron.

Enron's bankruptcy, which followed revelations that the firm had concealed debts using a complex series of external financial partnerships, made investors wary of all companies with unconventional business models or accounting methods.

On Monday, the SEC asked Qwest to submit documents on how it categorised certain types of revenues over the last two years.

The stock market watchdog opened an investigation into Global Crossing, the bankrupt fibre-optic cable telecommunications firm, in January.

Enron's auditors Andersen, heavily criticised for failing to flag up irregularities in the energy giant's accounts, also signed off Worldom and Qwest's books.