SAN FRANCISCO (AP) — Google is escalating its rivalry with Microsoft with the purchase of Quickoffice, the maker of a widely used mobile application for working on documents created in Microsoft’s programs for word processing, spreadsheets and presentations.

The deal announced Tuesday gives Google Inc. a new weapon to foil Microsoft Corp. as more people get work done on smartphones and tablet computers. Quickoffice makes those devices compatible with Microsoft Office even if the software suite isn’t installed on them.