Shares in US telecoms company Qwest Communications International fell after the firm revealed it had been contacted by officials probing the collapse of Global Crossing.

Qwest announced it had been officially asked by investigators at the Securities and Exchange Commission to provide documents relating to Global Crossing, which filed for Chapter 11 bankruptcy protection late last month.

The SEC is investigating Global Crossing after a letter from a former employee raised concerns about the firm's accounting practices.

Qwest shares fell $0.63 to $8.97 in early trade in New York on Monday.

The firm said it would co-operate fully with SEC investigators.