NEW YORK (AP) _ American Telephone & Telegraph Co. said Monday it increased its share in a joint European telecommunications venture with NV Philips to 85 percent from 50 percent.

Neither company would comment on how much AT&T paid to raise its percentage ownership of the venture, AT&T Network Systems International BV of Hilversum, the Netherlands.

AT&T said the action was in keeping with both companies' long-standing desire to bring in other companies as partners in the venture. AT&T does not want to retain its entire 85 percent stake indefinitely.

The venture, formerly named AT&T and Philips Telecommunications, was formed in 1984 mainly to sell switches and other equipment to Europe's government- owned phone companies. It had revenue last year of more than $600 million and about 5,000 employees. Marj McKean, an AT&T spokeswoman, said AT&T was not necessarily disappointed at the delay in getting other European partners, which could help the company expand its market share.

She said the venture was profitable last year, but could not say how large its profits were.