In what may be an unprecedented boost to the region's economy, Microsoft announced this morning that it will spend $1 billion and dramatically accelerate its plans for a massive campus redevelopment in Redmond.

The company plans to construct 1.1 million square feet of new space and add the 2 million square feet of space in the existing Safeco building. The total is as much space as two of Columbia Center towers and will create space for 7,000 to 15,000 new employees over the next three years.

When Microsoft first proposed its campus project a year ago, it said the project would be constructed over the next 10 to 20 years.

But Microsoft has increased hiring significantly over the past year as it prepares to release the biggest array of new products in its history.

Company officials are scheduled to announce the new plans at an 11:30 a.m. news conference with Gov. Christine Gregoire, King County Executive Ron Sims and Redmond Mayor Rosemarie Ives.