SEOUL, South Korea — South Korea’s Constitutional Court on Thursday ordered the government to introduce civilian forms of service for conscientious objectors, sparing hundreds of young men from going to prison each year for refusing to serve in the military for reasons of conscience or religious beliefs.

In a landmark decision, the court ruled that Article 5 of the country’s Military Service Act is unconstitutional because it does not offer such alternative services. It gave the government and Parliament until the end of next year to revise the law.

South Korea has prosecuted more young men for conscientious objection — almost all of them Jehovah’s Witnesses — than any other country, and it is one of the few that treat it as a crime without offering a different form of national service. Amnesty International says more than 19,300 South Korean conscientious objectors have gone to prison since 1953, when the Korean War ended in a truce.

“The state can no longer delay resolving this problem,” the court said in its 6-3 ruling, which held that Article 5 violated conscientious objectors’ freedom of conscience.