Roy Moore arrives at polling station on horseback, thanks Trump for support

Republican Senate candidate Roy Moore arrived on horseback as he prepared to cast his ballot in the Alabama Senate race on Tuesday, Dec. 12.

U.S. President Donald Trump has endorsed Moore, whose campaign has been clouded by allegations of sexual misconduct toward teenagers.

WATCH: Alabama voters head to polls to vote between Roy Moore, Doug Jones for Senate

1:07 Alabama voters head to polls to vote between Roy Moore, Doug Jones for Senate

Moore, a former Alabama Supreme Court chief justice, is battling Democrat Doug Jones, a former U.S. attorney who is hoping to pull off an upset victory in the deeply conservative Southern state.

Polls opened at 7 a.m. in the Alabama special election for the seat vacated by Republican Jeff Sessions, who became U.S. attorney general in the Trump administration.

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READ MORE: Alabama’s top court blocks order to preserve digital voting records in Tuesday’s election

The Alabama contest has divided the Republican Party on whether it is better to support Moore in order to maintain their slim majority in the U.S. Senate or shun him because of the sexual allegations.

Moore has been accused by multiple women of pursuing them when they were teenagers and he was in his 30s, including one woman who said he tried to initiate sexual contact with her when she was 14. Moore has denied any misconduct. Reuters has not independently verified any of the accusations.