WASHINGTON -- Jurors are too divided to reach a verdict in the first U.S. case involving an undercover sting operation to catch bribery of foreign officials.

Last year 22 businessmen who sell military equipment were arrested at a Las Vegas trade show where they anticipated picking up checks for supplies they sent to outfit Gabon's presidential guard.

But no officials from the central African nation were really involved in the fake $15 million deal that included a $1.5 million "commission" to the defense minister. The contracts were staged by the FBI.

Four men on trial in the first prosecution said it wasn't clear the commission was illegal since the word bribe was never used. Prosecutors said Thursday after Judge Richard Leon declared a mistrial that they plan to retry the case.