New Microsoft search engine Bing got a slight increase in their share of the U.S. search market in August, the third straight month of gains, according to tracking firm comScore online.

Bing, the Redmond, Washington-based software giant announced in late May, increasing its market share to 9.3 percent in August from 8.9 percent in July and 8.4 percent in June, comScore said Tuesday.

Google remains the undisputed leader of the U.S. search and lucrative advertising market last month with 64.6 percent market share, down from 0.1 percent in July.

The market share of U.S. Yahoo! was unchanged at 19.3 percent in August, according to comScore.

Ask search engine market share of 3.9 percent in August was also modified from July, while AOL scored a market share of 3.0 percent in August compared with 3.1 percent the month prev.

Yahoo! and Microsoft, after months of negotiations, released after 10 years of Web search and advertising partnership in late July that lays the groundwork for a joint offensive against Google.

Under the agreement, Yahoo! use the Microsoft search engine on their own sites, while Yahoo! provide the exclusive worldwide sales force for premium advertisers.

The agreement between the Internet portal and the software giant, which will be reviewed by U.S. regulators against the trust, is expected to close in early 2010.