Three American congressmen have written to the Federal Trade Commission asking them to investigate Google after media reports that the Internet giant was bypassing privacy settings of people using Apple's Safari Web browser on iPhones and computers.

The three want to know if Google's behaviour is a violation of a privacy settlement Google and the FTC signed last year. Breaches could bring fines of as much as $16,000 per violation per day.

The Wall Street Journal and CBS both ran major reports on the issue last week.

Google was said to have been tracking Web-browsing habits of people using Safari even if the users intended that kind of monitoring to be blocked.

Until recently, a page on Google's site told Safari users they could rely on the browser's settings to prevent tracking by Google.

"The FTC is aware of the situation," an agency spokeswoman told the WSJ.

Consumer groups have also asked the FTC to investigate. "Google falsely told Safari users that they could control the collection of data…when in fact Google was circumventing the preference," according to John Simpson, of Consumer Watchdog.

Google said it had stopped its practices and deleted the associated tracking files, after being contacted by the Journal.

On the letter to the FTC from the congressmen - Edward Markey (D., Mass.), Joe Barton (R., Texas) and Cliff Stearns (R., Fla.) - a Google spokesman said, "We are taking immediate steps to address their concerns. We are happy to answer any questions regulators and others may have."

Sen. Jay Rockefeller , chairman of the Senate Commerce Committee, also said he planned to look into Google's behavior and whether it worked "to circumvent consumer choice."