Microsoft’s internet search engine Bing has reported a slight gain in its share of the US search market, while Google and Yahoo posted slight declines, according to a report from research firm ComScore.

Google remained the leader of the US search market. Its market share dropped to 64.7% in July from 65% in June.

Microsoft’s Bing has grabbed 8.9% of the US internet searches in July, up 0.5 percentage points from June. The search market share of Yahoo! has declined 0.3 percentage points to 19.3% from 19.5% in June.

Ask.com has remained the fourth largest US search engine accounting 3.9% of the US search market in July, unchanged from June, while AOL captured 3.1% of the market share, also unchanged from July.

In July 2009, Americans conducted nearly 13.6 billion core searches, with Google accounting for 8.9 billion searches, followed by Yahoo! sites with 2.6 billion, Microsoft sites for 1.2 billion, Ask Network with 536 million and AOL 424 million.

Last month, Yahoo and Microsoft entered into 10-year internet search partnership with Microsoft Bing search engine powering the searches on both companies’ sites and Yahoo selling ads on both sites. The deal is subject to review by the anti-trust regulators.