JERUSALEM (JTA) — The Israeli soldier convicted of shooting a downed Palestinian terrorist entered military prison to begin serving his 18-month sentence.

Elor Azaria arrived at a military base in the center of the county on Wednesday, a day after the Military Court of Appeals denied his request to delay the beginning of his sentence until IDF Chief of Staff Lt.-Gen. Gadi Eisenkot decides whether or not to commute his sentence. The appeals court upheld his conviction and sentence last week.

Dozens of supporters waited outside the Tzrifin military base and cheered for him as he exited his car.

In a statement posted on Facebook on Friday, Azaria wrote in part: “I promise you that I acted out of a sense of immediate danger at the scene of the attack. But the court gave its ruling, and we live in a nation of laws. So I’m going to serve the prison sentence handed down, in the hope that it will be reduced.”

“It’s important to me to emphasize: I grew up in an ethical and moral home. If I’d known the terrorist didn’t have a bomb, I wouldn’t have opened fire. The lives of the warriors around me and my own life were my consideration at the scene. At the end of the day, I’m going to prison with my head held high,” he also wrote.

In a message he directed to young Israelis, he wrote: “We have one country, let’s protect it. I don’t want to think about the possibility that your motivation was harmed by my case. That must not happen. Go to combat [units]. Volunteer. Give as much as you can, for the nation and the country. We have no other country.”

Azaria, who was sentenced in February, has been under house arrest since leaving the military last week. He had been confined to the closed Nachshonim military base since being arrested in March 2016.

A medic in the elite Kfir Brigade, Azaria came on the scene following a Palestinian stabbing attack on soldiers in the West Bank city of Hebron on March 24, 2016. One assailant was killed, and Abdel Fattah al-Sharif was injured. Minutes later, while Sharif was lying on the ground, Azaria shot him in the head in a shooting that was captured on video by a local resident for the Israeli human rights group B’Tselem.

Azaria was arrested the same day and indicted nearly a month later. Autopsy reports showed that the shots by Azaria killed Sharif. Prior to shooting Sharif, Azaria had cared for a stabbed soldier.