On Tuesday six US stated requested to a Washington court to extend the official antitrust supervision of the biggest software company, Microsoft, for five more years.

Five years ago, in 2002, Microsoft, the U.S. Justice Department and 17 states reached a settlement after the government sued Microsoft for using its Windows monopoly to drive Internet browser Netscape out of the market.

The 2002 settlement will expire in November this year, but today sis states, led by California, said that the government should continue its judicial supervision in order to ensure that Windows Vista operating system continues to comply with the antitrust settlement.

"Microsoft continues to have a stranglehold on the two products, Windows and IE, that almost all consumers use for accessing these Web services and applications," Stephen Houck, an attorney representing California told US District Judge Colleen Kollar-Kotelly.

An extension would "make sure" Microsoft can't "abuse its still considerable market power to undermine" what it "considers emerging technologies" that threaten the monopoly, Houck added.

The states that joined California in this request are Connecticut, Iowa, Kansas, Massachusetts and Minnesota.

A spokesman for Microsoft said that the company is surprised that the states are requesting an extension, because previously they they criticized the settlement as ineffective. The next court hearing is scheduled for November 6.