Oakland International Airport has reopened after Terminal 1 of the California air hub was shut down for about four hours on Tuesday morning. A "suicidal man with a knife" had threatened to hurt himself, authorities said. No one was injured during the incident, and the man will be hospitalized for psychiatric help. 

The incident began around 5:45 a.m. and ended around 9:30 a.m., KPIX-TV reports. The man, said to be in his thirties, passed a note to a Transportation Security Administration (TSA) employee which read "Help me" and proceeded to pull out a large knife, which he held to his throat, according to KTVU.

Law enforcement arrived, and the Alameda County Sheriff's Office began tweeting updates at 10 a.m.

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"We have a suicidal man with a knife threatening to harm himself. Deputies and crisis negotiators are speaking with the man to get him help," the sheriff's office said of the scene. "Terminal 1 has been evacuated while we work through the issue. Stay tuned."

"Our crisis intervention deputies are on scene trying to negotiate with the individual in crisis," officials followed up, specifying that the incident was in the baggage claim area of the terminal near the checkpoint. "He’s obviously suffering from a severe mental health crisis. We are working with him."

At 11:30 a.m., the sheriff’s office said that responders were "still negotiating" with the man, who had not threatened to harm anyone besides himself.

An hour later, the Alameda County Sheriff's Office tweeted that airport liaisons were able to start sending customers through Terminal 2 to get to their scheduled flights. Negotiations with the unidentified man continued, and the evacuation of the airport terminal affected flights for Hawaiian Airlines, Alaska Airlines, Delta Air Lines and Frontier Airlines.

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Shortly after 1 p.m., authorities announced that the situation had been resolved and that no one was injured in the standoff.

"Deputies were able to deploy a taser after several hours of negotiations to bring the situation to a safe resolution. One of our sergeants briefly engaged in a struggle with the subject who was able to maintain his hold on the knife," the sheriff’s office tweeted.

"The subject caused a minor injury to his neck, but no one had was injured, including the sergeant who wrestled the knife away from him."

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Alameda County Sheriff's spokeswoman Tya Modeste told the outlet that the man was "highly agitated." Operations at Terminal 2 proceeded as usual while Terminal 1 was briefly shut down.

At 1:15 p.m., authorities announced that Oakland Airport was open once again. 

"The airport has reopened and the subject is en route to the hospital for psychiatric help," officials tweeted. "We are proud that our deputies were able to safely resolve this incident using de-escalation and a great deal of patience."