The state of Virginia and Fairfax County each pledged $600,000 to entice International Business Machines Corp. to bring 1,250 high-paying new government contracting jobs to Fairfax.

Economic development officials described the $1.2 million commitment of funds for improved roads and infrastructure yesterday in confirming plans, first reported last week, for a major expansion at the computer giant's Fair Lakes site.

The workers hired at the Fair Lakes site will be part of IBM's government contracting division, a unit with average salaries topping $90,000. The average salary for all workers in Fairfax County was $52,394 as of 2002, according to the Commerce Department.

"It's huge for us, not just for the number of jobs and the types of jobs, but also just because it's IBM," said Gerald L. Gordon, president and chief executive of the Fairfax County Economic Development Authority. "IBM is world-class for us."

The deal is Virginia's largest private-sector job announcement in the past three years, according to Jill Lawrence Vaughan, a spokeswoman for the Virginia Economic Development Partnership.

IBM's expansion in the county will include a $10 million investment for new technology and building renovations. The new jobs come as part of IBM's effort to strengthen its consulting and services units. The company plans to create 18,800 jobs throughout the world this year.

IBM already employs about 7,800 people in Washington area, including 4,000 in Virginia and 3,800 in Maryland. Most of IBM's local employees work in the government sector. New hires at the Fair Lakes facility, who will be added over the next 18 months, will work as business and security analysts, network engineers and systems integrators.

The deal was officially announced yesterday at the annual Commonwealth of Virginia's Information Technology Symposium in Norfolk.

The office of Gov. Mark R. Warner (D) learned of IBM's proposed expansion in April and assigned a project manager to focus on developing an incentives package for the company, according to Vaughan of the Virginia Economic Development Partnership, a business-government alliance. Virginia was in competition with several other states, including Maryland, she said. Along with the infrastructure improvement funds, IBM will receive an undisclosed amount of funding for workforce training from Virginia's Department of Business Assistance.

The economic incentives Virginia offered helped sway the company, said Christopher G. Caine, IBM's vice president of government programs, but it was the state's skilled technical workforce that ultimately pushed the commonwealth ahead of its competition. About a third of the new jobs will go to recent college graduates, while the rest will be professionals with experience, he said.

"The kind of environment that makes sense for IBM to invest in combines skills, infrastructure and investment in a community. . . . Virginia has demonstrated good leadership in all three of those areas," Caine said.