WASHINGTON (AP) — Democratic candidates in many pivotal Senate races are raising more money than their GOP counterparts, but they'll need the cushion to counter spending by independent conservative groups determined to win a Republican majority.

Democrats outraised Republicans in seven of 10 key races in the April-June period, according to quarterly reports that had to be filed by midnight Sunday with the Federal Election Commission. In Hawaii, New Mexico and North Dakota, GOP candidates had a fundraising edge.

One roadmap of the most competitive races is where American Crossroads and its affiliate, Crossroads GPS, are spending their money. The groups, guided by former Bush political adviser Karl Rove, recently announced they had reserved $23.5 million of TV air time for Senate campaign ads this fall in six states: Missouri, Nevada, Florida, Virginia and Ohio in addition to North Dakota. Altogether, Crossroads plans on spending $70 million supporting Republican Senate candidates in the fall.