A Greek police officer accused of shooting and seriously injuring a Roma teenager during a chase over an allegedly unpaid petrol station bill will remain under house arrest, after a prosecutor and an investigating judge disagreed on whether he should be detained until his trial.

About 200 protesters from the Roma community were gathered outside the courthouse in Greece’s second-largest city of Thessaloniki on Friday, where the 34-year-old officer appeared amid tight security.

The officer has been charged with attempted manslaughter with possible intent, and one count of illegally firing his weapon over the shooting on Monday, which has left the 16-year-old in a critical condition in hospital with a head wound.

Police have claimed the teenager tried to ram a police motorcycle involved in the chase, and the officer said he had fired his weapon because he believed his colleagues’ lives were in danger.

The prosecutor handling the case recommended that the officer should be remanded in custody until the trial, while the investigating judge who questioned the officer in court on Friday recommended he should be released on bail.

Until a panel of judges resolves this disagreement, the officer will be placed under house arrest. The prosecutor has three days to make another recommendation to the panel, and a decision could come as early as next week.

Security was tight at the courthouse for the hearing, with riot police forming a cordon and the police officer surrounded by dozens of his colleagues as he arrived for questioning.

Friends and relatives of the injured 16-year-old and other protesters from the Roma community gathered outside the courthouse, holding up photos of the youth and calling for justice.

The shooting has already sparked days of violent protests by members of the Roma community in Greece’s second-largest city, as well as Athens and other areas, with vehicles and at least one business torched and police coming under fire from shotguns.

“It wasn’t the petrol, it wasn’t the money, the cops shot because he was Roma,” the protesters chanted outside the courthouse before the decision on the officer’s house arrest was made public. Some burned 20 euro notes – the amount the teenager allegedly failed to pay at the petrol station.

Community leaders have called for a peaceful protest outside the courthouse.

Panagiotis Sabanis, head of the Roma Federation of Central and Western Macedonia, said: “We want justice. The crime was racist.

“There is racism against us in Greece. It’s not the first incident of a police shooting against a Roma just because he is a Roma.”

Several Roma men have been injured or fatally shot in recent years during confrontations with police while allegedly seeking to evade arrest for breaches of the law.

Andonis Tasios, general secretary of the Roma community, where the boy lives, was among the protesters outside the court on Friday. “They shot him because of his colour,” he said.

“If he wasn’t Roma, they wouldn’t have done it.”

Members of the Roma community in Greece have long faced discrimination and many often live on the margins of society.

The 16-year-old, who was chased by motorcycle police after he allegedly drove away from a petrol station without paying the 20 euro (£17) bill early on Monday, was hit in the head and remains in hospital in a critical condition.

In a preliminary court appearance earlier in the week, the police officer said he fired his weapon because he feared for the lives of his colleagues, but he had not aimed at the youth.

During his questioning on Friday, the officer said the youth had tried to ram the motorcycle three times.