Sina ( SINA - Get Report) said Thursday it had been penalized by one of China's major mobile telephone carriers.

The sanctions -- part of a recent crackdown on companies that provide content for Chinese mobile phone companies -- sent Sina's shares down as much as 9% Thursday morning, though the stock recovered at midday to trade only 4% lower. Shares in other Chinese Internet and wireless portal stocks slid as well.

Sina said China Mobile ( CHL) was continuing an earlier suspension of Sina's main interactive voice response service number, pending further study by China Mobile of Sina's proposed changes to its IVR service.

In addition, Sina said China Mobile was imposing a three-month suspension of approval, as of Aug. 15, on certain new products and services, and a six-month suspension of approval for other new products and services.

A month ago, Sina disclosed that China Mobile had suspended its IVR service for violation of certain operating policies. Sina says that in the quarter ended June 30, IVR had amounted to 4% of total revenue. The company didn't speculate Thursday on the financial impact of the new-products-and-services suspension.

Sina isn't alone in facing a crackdown by China Mobile on content it offers over China Mobile's network. Sina indicated Thursday that it was one of 27 companies offering value-added wireless services that China Mobile alleged had violated its policies. In addition, the Chinese Internet portal ( SOHU - Get Report) said last month that China Mobile had suspended its wireless messaging services for a year, citing's unauthorized transmission of a marketing message to 1,374 wireless phone users in Sichuan Province. also said that certain China Mobile subsidiaries had instructed the company and other service providers to cut fees on their short messaging service offerings.

Sina's shares were trading at $20.25 Thursday morning, down $1.04 for the day and down some 60% from the stock's January high. Like other Chinese portal stocks, Sina's shares zoomed skyward in 2003, thanks to investors' hopes that the Chinese Internet boom would duplicate the explosive growth of turn-of-the-century Internet use in the U.S.