Microsoft CEO Steve Ballmer vowed to "kill" Internet search leader Google in an obscenity-laced tirade, and Google chased a prized Microsoft executive "like wolves," according to documents filed Sept.

SAN FRANCISCO (AP) -- Microsoft CEO Steve Ballmer vowed to "kill" Internet search leader Google in an obscenity-laced tirade, and Google chased a prized Microsoft executive "like wolves," according to documents filed Sept. 2 in an increasingly bitter legal battle between the rivals.

The allegations, filed in a Washington state court, represent the latest salvos in a showdown triggered by Google's July hiring of former Microsoft executive Kai Fu-Lee to oversee a research and development center that Google plans to open in China. Lee started at Google the day after he resigned from Microsoft.

The tug-of-war over Lee -- known for his work on computer recognition of language -- has exposed the behind-the-scenes animosity that has been brewing between two of high-tech's best-known companies.

Ballmer's threat last November was recounted in a sworn declaration by a former Microsoft engineer, Mark Lucovsky, who said he met with Microsoft's chief executive 10 months ago to discuss his decision to leave the company after six years.

After learning Lucovsky was leaving to take a job at Google, Ballmer picked up his chair and hurled it across his office, according to the declaration.

Ballmer then pejoratively berated Google CEO Eric Schmidt, Lucovsky recalled.

"I'm going to f------ bury that guy, I have done it before, and I will do it again," the declaration quotes Ballmer. "I'm going to f------ kill Google."

Before joining Google, Schmidt was a top executive at Sun Microsystems and Novell, a pair of tech companies that Microsoft has previously battled.

In a statement Sept. 2, Ballmer described Lucovsky's recollection as a "gross exaggeration. Mark's decision to leave was disappointing and I urged him strongly to change his mind. But his characterization of that meeting is not accurate."

Microsoft is suing to prevent Lee from leading Google's China expansion, maintaining those duties would violate the terms of a noncompete agreement that he signed as part of his employment contract.

Mountain View-based Google has depicted Microsoft's lawsuit as a form of intimidation designed to thwart a fast-growing rival that has emerged as a formidable threat to the Redmond, Wash.-based software maker.

The Lucovsky declaration is just one piece of evidence that Google has filed in an attempt to prove that Microsoft is on a vendetta.

Microsoft won the first round in the case in late July when King County Superior Court Judge Steven Gonzalez issued an order temporarily barring Lee from performing the duties that Google hired him to do. The two rivals are scheduled to face off in court Sept. 6 when Microsoft will ask Gonzalez to extend the order against Lee and Google until the case goes to trial in January.

As it tries to make its case, Microsoft is attempting to demonstrate that Google wanted Lee largely because he knows intimate details about Microsoft's strategy for expanding in China and for the booming search engine market.

In its brief Sept. 2, Microsoft alleged that Lee sent confidential documents about the company's China strategy to Google a month before he was hired, although Google insists all the material that Lee relayed to Google had been made public previously.

Microsoft also released an e-mail from Jonathan Rosenberg, Google's director of business development, in an attempt to prove the company wants Lee for other projects besides the new China center.

"I all but insist that we pull out all the stops and pursue him like wolves," Rosenberg wrote of Lee. "He is an all-star and will contribute in ways that go substantially beyond China."

Before resigning from Microsoft, Lee began to help Google plot its China strategy with a series of suggestions, including recommending possible sites for the new office, according to Microsoft's brief.

Microsoft alleged Lee's insights helped him win a Google contract worth more than $10 million -- a package that Google itself described as "unprecedented" for the company.

Google paid Lee a $2.5 million signing bonus and promised a $1.5 million bonus after one year, plus a $250,000 salary and options on 10,000 shares of Google stock, according to court documents. If he stays for four years, Lee also will receive another 20,000 Google shares, currently worth $5.8 million.

Lee also demanded that Google pay all his legal fees if Microsoft sued, a request that was granted.