The Internal Revenue Service, noting an escalation in identity theft scams, is raising alarms about e-mails designed to dupe taxpayers into revealing personal financial information.

IRS and Treasury Department officials have noticed an increase this winter in the frequency and sophistication of "phishing" schemes that use the tax agency's logo to lure victims.

"There does seem to be a proliferation of them this filing season," Richard Morgante, commissioner of the IRS wage and investment division, said Monday. "We have more thieves trying to take advantage of the filing season than we've seen in the past."

The Treasury Inspector General for Tax Administration, which investigates groups or individuals impersonating the IRS, found 12 separate Web sites hosting such "phishing" schemes operating in 11 different countries, from the United States to Aruba to Korea.

In a "phishing" scam, identity thieves send e-mail masquerading as official communication from a government agency, bank or other institution in an attempt to solicit personal data from victims. The data could include financial account numbers, passwords, credit card numbers or other information.

The thieves use the information to steal a person's identity and commit financial crimes, like using the victim's credit cards or opening new ones, applying for loans or filing fraudulent tax returns.

"Phishing" e-mails purporting to come from the IRS often tell taxpayers they're due a refund and direct them to a false IRS Web site. The e-mail address may include "irs.gov," such as tax-refunds@irs.gov or admin@irs.gov.

The communication and Web sites might look like the real thing, but they're not, Morgante said. The IRS does not communicate with taxpayers via e-mail, nor does the IRS ask people for passwords, personal identification numbers or other secret information about financial accounts.

Taxpayers who file their tax returns electronically might get an e-mailed acknowledgment when the return is accepted, but that e-mail would come from the company providing tax software or professional preparation services, not the IRS.

Taxpayers can check the status of their refund through the IRS Web site. That tool asks taxpayers for their Social Security number, filing status and the exact refund due.

Those who receive fraudulent IRS e-mail can contact the Treasury Inspector General for Tax Administration at 1-800-366-4484.