The IRS on Friday delayed upcoming tax deadlines for a week nationwide as millions of taxpayers struggle to meet their obligations in the aftermath of the terrorist attacks. 

A Monday deadline facing people who make quarterly estimated tax payments was moved to Sept. 24. About 13 million taxpayers pay estimated taxes of more than $190 billion a year, according to the Internal Revenue Service. 

The Sept. 24 deadline also will apply to certain corporations that had gotten a six-month extension, expiring Monday, to pay their taxes. 

The destruction of the World Trade Center in New York is the main reason people are having problems paying taxes. With stock markets closed, some taxpayers can't raise the cash to pay the IRS. Computer systems are down, buildings are shuttered and records in some cases are missing or unreachable. 

``We want to reduce burdens on taxpayers during this tragic time,'' said IRS spokesman Terry Lemons. ``We're trying to be flexible as new problems arise.'' 

The announcement followed a meeting Friday in which major tax practitioner groups outlined the national ramifications for IRS Commissioner Charles Rossotti and top Treasury Department officials. 

The IRS previously said that taxpayers directly affected by the attacks - especially those in the disaster areas - would have until Jan. 15 to pay estimated and corporate taxes. Many penalties and enforcement activities are also being suspended for six months. 

Taxpayers who believe they are entitled to this relief should write in red ink on the top of their returns: ``Sept. 11, 2001 Terrorist Attack.''