The justice department and 20 states have charged that Microsoft Corporation violated the nation's antitrust laws by competing unfairly against Netscape Communications Corp in the market for Internet browsers.

Apple executive Avadis Tevanian also testified about unfair tactics Microsoft allegedly used against his company in the market for multimedia software, which bear an eerie resemblance to tactics described by Netscape executives as having been used against their company.

Tevanian will be cross-examined on his written testimony, which was made public on Friday, when the Microsoft trial starts its third week on Monday.

Apple makes its own computers and operating system, one of the few competitors to Microsoft's Windows operating system for personal computers.

Microsoft's Windows commands more than 90 per cent of themarket, while Tevanian said that in 1997 his company's operating system had 3.5 per cent.Apple computers featured the Netscape Navigator Web browser until Microsoft leaned on it, Tevanian said.

He testified that Microsoft held a monopoly in the office application with its office suite, which included the Word word processor, a spreadsheet and other programmes.

Microsoft makes a version for Apple Macintosh computers, and Tevanian testified it was ``critical to the commercial viability'' of Apple Computers to sell the product.

``Microsoft was aware that Apple desperately needed to maintain support for Microsoft office for Macintosh,'' he said.

Microsoft conditioned its continued support for Microsoft office on Apple's agreement to feature Microsoft's Internet Explorer over Netscape Navigator, he said.

``If Microsoft had not exercised its monopoly power in the office application market by threatening to stop support for office for Macintosh, Apple would not have resolved the disputes'' in favour ofInternet Explorer, Tevanian said.

In addition, Tevanian described Apple's own troubles with Microsoft over its multimedia QuickTime technology, which plays audio and video content and shows pictures.

Tevanian described a series of meetings called by Microsoft, ostensibly to discuss licensing codes.

In fact, he said, Microsoft used those meetings to pressure Apple ``to abandon its business of providing software that enables users to view multimedia content.''

``In return, Microsoft offered Apple the much smaller portion of the market for software tools used to create multimedia content,'' Tevanian said.

That echoes government accusations that at a June 21, 1995, meeting, Microsoft told Netscape to abandon the browser market for its Windows 95 operating system and instead be satisfied with the much smaller market of Web browsers for other operating systems.

In another meeting, Apple was told to abandon the playback segment of the multimedia market, Tevanian said.

Tevanian testified that inSeptember 1997, Eric Engstrom, the manager of Microsoft multimedia technology, said ``if necessary, Microsoft would assign 150 engineers'' to compete with Apple.

``At that time, Apple's entire QuickTime engineering group consisted of approximately 100 engineers,'' Tevanian said.

In a statement, Microsoft said: ``Microsoft and Apple continue to be great partners after more than 17 years of both competing and cooperating in the software industry. Microsoft today reiterates its strong support for the Macintosh and our Macintosh customers.''