WASHINGTON —  The estate of pop music legend Michael Jackson owes $702 million in federal taxes and penalties, according to the Internal Revenue Service, which accused the estate of undervaluing some of the star’s assets by hundreds of millions of dollars.

The dollar amounts in dispute had not been previously disclosed in the court challenge that the Jackson estate filed in July to a bill from the IRS.

Jackson died on June 25, 2009, the date of the estate tax return. His estate’s beneficiaries are Jackson’s mother, Katherine, his three children and charities.

The estate’s 2009 tax filing said the total Jackson estate had a $7 million taxable value. In May, the IRS issued the estate a tax deficiency notice for $505.1 million in taxes and $196.9 million in penalties, according to tax court documents released last weeks.

A Jackson estate spokesman said the IRS’s appraisal values “were based on speculative and erroneous assumptions unsupported by the facts or law.”

Under tax court rules, the Jackson estate will not need to pay any taxes or penalties, unless the court rules in favor of the IRS.