The latest trickery employed by pranksters who try to use the Internal Revenue Service as a means for legitimizing tax scams has placed families of those serving in the U.S. military on high alert.

Two scams targeted at military families have surfaced this week, according to Mark Everson, newly appointed commissioner of the IRS.

In one scam, families are contacted by telephone and told they are speaking with a representative from the IRS. They are informed that because they have a family member serving in the military they are entitled to a special $4,000 tax refund. In order to receive the refund, the families are told they must pay a $42 fee that covers postage. The military families are then asked for a credit card number to pay for the $42 fee.

To add legitimacy to the story, telephoners provide a call-back number which is the IRS toll-free hotline.

There is no $4,000 tax refund available for families of members in the armed forces. People who provide their credit card number over the telephone are opening themselves up to identity theft and unauthorized use of their credit card.

The other new scam is appearing in e-mail messages, again to military families. The message appears to have been sent by the IRS. Taxpayers are urged to follow a link to a Web site where they are asked to fill in personal and financial information. The Web site referred to in the e-mail message is not an IRS site.

Mr. Everson reminds taxpayers that IRS employees do not request credit card numbers, nor do they require a fee for the processing or postage relating to refunds. "These types of shameless schemes hold out the allure of easy money," he said. "And we urge taxpayers to remember that the IRS does not charge for refunds or solicit credit-card information."