JERUSALEM — The Israeli military has jailed a young man for six months for refusing to serve because of his opposition to Israel's occupation of the West Bank, focusing attention on the longstanding conflict between the country's universal military service and divided political beliefs.

The refusal by 20-year-old Natan Blanc to serve has put the military in a delicate position as it tries to resolve the case. Releasing him could set an unwanted precedent, but keeping him jailed could turn into a public-relations debacle.

Last week more than 30 Israeli legal experts, including the dean of Hebrew University's law school, signed an open letter urging the army to release Blanc and saying the detention violated his freedom of conscience.

On Tuesday, several dozen of his supporters demonstrated outside Israel's military headquarters.

Blanc's father, David, said his son was supposed to be inducted for compulsory military service last November, and after declaring his refusal to serve, he was sent to a military prison. Since then, he has been sentenced to a series of 10 consecutive terms totaling 178 days in jail, with no end in sight.

The younger Blanc, in a videotaped statement made several months ago, said that he objects to Israel's occupation of the West Bank.

"The main reason that I am refusing to serve is that I feel that our country is going toward a non-democratic situation of civil inequality between us and the Palestinians, a situation in which there are two peoples in the same state, one of which has the right to vote and participate in elections, and the other does not," he said. "I believe the Israeli military plays a major role in preserving this situation, and my conscience does not allow me to participate in it."

Israel rules over more than 2 million Palestinians in the West Bank and east Jerusalem, areas it captured in the 1967 Mideast war. West Bank Palestinians do not have the right to vote.

While east Jerusalem Palestinians are eligible for Israeli citizenship, most reject Israeli control and few have accepted the offer. The international community considers both areas, which the Palestinians claim for a future state, to be occupied.

Most Israelis, including Prime Minister Benjamin Netanyahu, say that establishment of a Palestinian state is the only way to preserve Israel's Jewish majority. Without a partition of the land, most demographers believe the number of Arabs living under Israeli rule could soon outnumber the Jewish population. Peace talks have been stalled for more than four years.

In Israel, military service is compulsory, with men serving three years and women doing about two. But in reality, thousands of Israelis are given automatic exemptions, including ultra-Orthodox religious men, Arab citizens, married women and people with health issues. In addition, young religious women often serve civilian national service instead of in the military.

Blanc has requested that he be allowed to serve in Israel's civilian paramedic service. But when it comes to people who want to avoid service on ideological grounds, the army takes a tough line.

"Israel today has a compulsory draft that applies to all men and women in Israel, with a few exceptions granted due to health-related issues, religious reasons, place of residence and more," the military said in a statement. "Civilians who do not receive exemption from the (military) but refrain from following the law face the consequences of their actions. This holds true in the case of Natan Blanc as well."

The army would not provide statistics on the number of conscientious objectors, but outside experts said they are relatively rare.

Ishai Menuchin, an activist in the Israeli group Yesh Gvul, which assists soldiers who object to the occupation, estimated that dozens of Israeli youths refuse to serve each year.

Earning an exemption as a "pacifist" requires approval from a special committee and is almost never granted, he said. In most cases, the military dismisses objectors as "unfit" for physical or psychological reasons. A small number are sent to jail for short stints, and then agree to meet with a mental health officer to receive an exemption on psychological grounds.

"The army prefers this. You accept that there is something wrong about you," he said.

But Blanc has refused to leave on psychological grounds.

"He's not going to lie to get out. That's apparently what's required," said Blanc's father.

Earlier this month, Blanc was handed a 10th sentence, this time 28 days. According to Yesh Gvul, it is the most trials an objector has had, though several have spent longer behind bars.

"We know he is stubborn. But we didn't realize it would go on this long," said David Blanc. "His principles are what they are."

The elder Blanc, who said he was an officer in the military, said he respects his son's decision. "He should certainly follow his conscience," he said. "I think I'm proud for standing up for what he believes in."

Moshe Yinon, a former military judge, said the army can often find ways to accommodate young Israelis who oppose serving, but it draws the line at political objections. He said the army differentiates between "pacifists," who oppose any use of violence, and "selective objectors" who oppose certain Israeli policies. Blanc would fall into that second category.

"There is no place for political ideas in the army. It's a matter of principle," he said. During Israel's withdrawal from the Gaza Strip in 2005, for example, soldiers were jailed for refusing to participate in the evacuation of Jewish settlers, he said.

Yinon said it was difficult to predict how the case will be resolved. So far, Blanc's punishments have been meted out by a local commander. But at some point, the case could go to a full trial, which could turn into an unwanted public spectacle.

"There is always a dilemma. How long are we going to let this go on?" he said.