Two third-party spending groups this week announced dropping more than $900,000 for ads in the Alaska U.S. Senate race.

The buys -- in addition to the millions that groups have already spent or are expected to spend -- underscore the intense interest in the race, which could help determine which party controls the Senate.

The Karl Rove-affiliated American Crossroads, in its latest ad, suggests Democratic Sen. Mark Begich takes credits for things he didn't do, at least on his own.

Meanwhile, the pro-Begich Put Alaska First PAC reported nearly $500,000 for an ad that continues hammering away at Republican candidate Dan Sullivan over a permitting bill he supported while state Natural Resources commissioner.