CHARLOTTE, N.C. (AP) — A 21-year-old Charlotte man has been arrested by the Secret Service for allegedly posting threats to kill President Barack Obama on Twitter.

Authorities said Donte Jamar Sims was detained Wednesday. The Secret Service says Sims posted messages including one that said, "Ima Assassinate president Obama this evening!" on Monday morning, two days before Obama arrived in Charlotte for the Democratic National Convention.

Investigators say Sims told them he hated the president and was high on marijuana when he made the posts. When he found out he was being arrested, he wrote a written apology.

It wasn't immediately known if Sims had a lawyer. If convicted, he faces up to five years in prison.