Uber Technologies Inc is teaming up with Baidu Technologies Inc and Apax Partners to pursue Nokia Oyj's maps business, people with knowledge of the matter said, as a bidding war for the unit intensifies.

Another group, comprising China's Tencent Holdings Ltd, NavInfo Co and Swedish buyout firm EQT Partners AB, is also bidding for the unit, which may fetch as much as $4 billion, three of the people said, asking not to be identified because negotiations are private.

Microsoft Corp has offered to buy a minority stake, while three US private-equity firms - Hellman & Friedman, Silver Lake Management and Thoma Bravo - are also in the running, the people said.

The next round of bids for the maps unit, known as HERE, is due in two weeks, they said. Baidu, China's largest search engine, is partnering with Uber, the San Francisco-based taxi challenger, to avoid regulatory scrutiny, one of the people said. A group of German carmakers comprising Audi AG, BMW AG and Daimler AG is also interested in the business, two of the people said.

Representatives for Audi, Apax, Baidu, Daimler, EQT, HERE, Hellman & Friedman, Microsoft, Nokia, Tencent, Silver Lake, Thoma Bravo and Uber declined to comment.

Nokia's digital-maps business provides data to Amazon.com Inc, Microsoft and Yahoo Inc and car-navigation systems for companies including Toyota Motor Corp and Honda Motor Co. The potential valuation suggests Nokia's mapping assets have lost value since 2008, when the company spent $8.1 billion to buy map provider Navteq Corp.

Still, with bidders lining up, the potential value of the sale could be climbing: as recently as April the company was said to be seeking more than 3 billion euros ($3.4 billion). The company had also sought bids from companies including Facebook Inc and Alibaba Group Holding Ltd, people with knowledge of the matter said last month.

Nokia, based in Espoo, Finland, is seeking to sell the mapping unit as it focuses on mobile-network equipment and services to better compete with Huawei Technologies Co. Nokia agreed to buy Alcatel-Lucent SA for 15.6 billion euros last month to create the world's largest supplier of equipment that powers mobile-phone networks.