MOUNT HAZEKA, Israel » Elite infantry and reconnaissance units have been moved into the long-quiet Golan Heights this spring. Bulldozers are making way for new military shelters. And at a strategic Army outpost, a Merkava tank sits pointing toward Syria — poised to race up a dirt ramp at a moment’s notice.

The stepped-up military presence across the 43-mile border with Syria demonstrates the growing fear and anxiety among Israeli political and military leaders over the Syrian civil war now in its third year. Already there have been clashes at the border, with errant munitions landing in the Golan some 30 times, at least five prompting Israel to fire back.

But the concern runs deeper along what was for decades one border that Israel did not have to worry much about. Many increasingly see no possible positive outcome of their neighbor’s bloody conflict, no clear solution for securing their interests in the meanwhile. Israel’s military leadership now views southern Syria as an "ungoverned area" that poses imminent danger.

"This is the new reality of the Golan Heights," Brig. Gen. Gal Hirsch, an active-reservist who is deputy commander of a unit focused on long-range operations in enemy territory, said as he stood near the Merkava tank positioned here. "Inside the bush, we have units that are ready to jump and open fire. You can see here tanks, you can see forces — and there are many things you cannot see."

For Israel, as for other nations, the Syrian civil war presents pressing security challenges including the prospect of chemical and other sophisticated weapons falling into the hands of rogue groups, and radical Islamists ultimately coming to power. But speaking to members of Parliament from his faction this week, Prime Minister Benjamin Netanyahu signaled a new focus, saying, "The first and primary threat is an attack on our citizens and soldiers from the Golan Heights line."

And so, as Israel is building up its defense here, the nation is debating a longer-term approach, a prospect complicated and made more urgent by recent troubles along the border with Egypt, which had also been relatively quiet, until the overthrow of President Hosni Mubarak two years ago.

Some analysts in Israel and abroad have raised the possibility of Israel creating a buffer zone and arming a proxy force inside Syria, similar to what it did beginning in the 1970s with the South Lebanon Army. Although the Lebanese strategy was largely seen as having backfired by fomenting the emergence of Hezbollah, Netanyahu fueled that speculation when he declined in a recent interview with the BBC to confirm or deny whether Israel would arm Syrian rebels.

Others have suggested a force of Israeli citizens, perhaps made up of Druze who live in the Golan and are of Syrian origin, amassing in the buffer zone long patrolled by 1,000 U.N. peacekeepers. That force is itself in turmoil, with two nations having withdrawn their troops since December, and 21 Filipino soldiers having been kidnapped in March.

But top military and political officials in recent interviews said neither were on the table, revealing Israel’s quandary: Despite what it considers mounting threats, it sees few if any options for direct action.

"In so many cases," one Israeli general said in an interview last month, speaking on the condition he not be named, "we can be the sous chef, not the chef."

Israel and Syria are in a technical state of war but have maintained an uneasy calm since 1974 along the Golan Heights, which Israel seized in 1967 and much of the world considers occupied territory. With Syria now unraveling, Israelis are increasingly unclear about what outcome they are wishing for, with some privately suggesting the best circumstances might be for the conflict to continue so enemies including Iran and Hezbollah, the Lebanese Shiite militia, are occupied elsewhere.

Israel is wary of many of the rebel groups challenging the Syrian president, Bashar Assad, because of their affiliations with al-Qaida and jihadists, and worries that its vast neighbor will break up into fiefdoms far more likely to launch attacks than a centralized state.

Zalman Shoval, a former Israeli ambassador to the United States, invoked what he said was a Hebrew saying to sum up Israel’s options: "Between cholera and the plague." And Dore Gold, a longtime diplomat who now heads the Jerusalem Center for Public Affairs, said "the choices facing Israel are not good."

"All you can do," Gold said, "is make sure you make clear to all parties around you that you’ll do what’s necessary to exercise your right to self-defense."

The Israeli newspaper, Maariv, reported this week that a military post near the critical junction of Israel’s borders with Syria and Jordan was reopened after having been shuttered for years.

Hirsch, leading a border tour for journalists through closed military zones Thursday, said troops have not only multiplied across the Golan but have heightened their levels of alert. Late last year, Israel also began building a 16-foot steel obstacle equipped with sophisticated sensors and intelligence equipment behind the rusted, sagging, chest-high fence along the 43-mile border. It is scheduled to be completed in August.

"We want to make sure nobody will be able to penetrate from Syria to our territory for any purpose," Hirsch said as workers added circles of razor wire to the top two-thirds of the intimidating silver rebar wall, and readied some areas for a concrete foundation.

"The tanks were always ready behind," he added, "but now they are along the line, ready to fire."

Despite the increased military activity and new soundtrack of Syrian bombing, life in the Golan Heights, a lush, hilly, 444-square-mile swath of vineyards and orchards that is home to 43,000 Israelis, about half of them Druze, has not changed much. The Golan Tourism Association said it has received numerous inquiries about the Syrian situation but has seen no drop in the 3 million annual visitors since the conflict began. Local Druze continue to export apples to Syria, some 7,000 tons so far in 2013, on pace with the 18,000 sent in recent years.

In Alonei Habashan, the community of 57 religious Jewish families just behind the Israeli military post here that has been hit by Syrian shells several times, children continue to go to school and roam freely, according to Yael Saperia, a lawyer and mother of seven who has lived there 25 years. They have grown used to the sounds of war.

"It’s sort of become the background noise; we don’t even pay attention to it anymore," she said. "On Shabbat we hear it, mostly, because it’s quiet."

© 2013 The New York Times Company