The Houthis, Iranian-backed rebels in Yemen who have launched recent drone and missile attacks on Israeli and American targets, are emerging as an unpredictable and dangerous wild card in the Middle East — the proxies that Iran considers most suited to widening the war with Israel.

Analysts close to the Iranian government said the Houthis’ base in Yemen makes them ideally positioned to escalate fighting in the region, in the hopes of pressuring Israel to end its war with Hamas in Gaza.

The analysts’ assessment tracks with descriptions of a plan by Iran and its network of militias to increase attacks on Israeli and American targets in the region, according to two Iranians affiliated with the Islamic Revolutionary Guards Corps who were not authorized to speak publicly.

The Houthis, the analysts said, are Iran’s chosen proxies because from Yemen they are both close enough to the Red Sea’s strategic waterways to disrupt global shipping, and far enough from Israel to make retaliatory strikes difficult. Unlike Hezbollah, the Iranian-backed militant group that has struck Israel from Lebanon, the Houthis are not beholden to domestic political dynamics — making them effectively accountable to no one.

Two senior Israeli defense officials said their intelligence confirmed that Iran’s leaders were pushing the regional militias to intensify their attacks against Israel. They said Israel’s defense and intelligence circles were alarmed by the recent Houthi attacks and considered the threat serious enough that military intelligence had established a special unit dedicated to threats coming from Yemen. In recent years, they said, Israeli intelligence had also predicted the next war would be fought on multiple fronts, mentioning the Houthis and other Iranian proxies.

Already, the Houthis have used their proximity to major shipping lanes to attack commercial vessels and threaten U.S. warships. A further escalation along the same routes could disrupt global shipping, analysts said.

“We think Houthis in Yemen will become more of a threat to Israel in the long term than Hamas or even Hezbollah,” said Nasser Imani, a political analyst in Tehran who is close to the government. “Iran considers them a major player and part of the collective strategy of the resistance axis.”

On Thursday, John F. Kirby, a national security spokesman for President Biden, said the Houthi attacks threatened to escalate tensions in the region: “It’s clearly a risk to the potential widening and deepening of the conflict.”

The network of Iran-backed regional militias, known as the axis of resistance, includes Hamas and Palestinian Islamic Jihad in Gaza, Hezbollah in Lebanon and the Houthis in Yemen, as well as several militia groups in Iraq and Syria. Since Israel declared war on Hamas after the group launched a terrorist attack on southern Israel on Oct. 7, other axis members have opened secondary fronts against Israel in a restrained manner, stopping short of igniting an all-out war. Militias in Iraq and Syria have attacked American military bases more than 70 times with drones and rockets.

As Israel expands its war in Gaza — in which more than 15,000 people, many of them women and children, have been killed, according to Gazan health officials — the axis groups have concluded they must significantly raise the prospect of a regional war to force a cease-fire, according to the Iranians affiliated with the Revolutionary Guards.

The new plan includes Houthi attacks on Israeli and American-owned vessels operating in the Red Sea, according to the Iranians affiliated with the Guards. The Iran-backed militias in Iraq and Syria would also increase their attacks on American military bases with the intent to cause harm and damage, they said.

An additional aim, they added, is to destabilize maritime security, global shipping and energy supplies.

Iran’s Revolutionary Guards are providing the Houthis with intelligence to help identify Israeli-owned vessels in the Red Sea, said the two Iranians.

Western officials have said the intelligence is gathered by a ship operated by the Guards near the coast of Yemen. More recently, both a senior Western defense official and one of the Iranians familiar with the planning said Iran also had set up an intelligence outpost in the south of Iran to pass along information on Israeli ships to Houthis.

Iran’s foreign minister, Hossein Amir Abdollahian, has denied, publicly and in a recent interview with The New York Times, that Iran controls the Houthis and other militia groups. But senior Iranian military officials and advisers have said in public speeches and in social media posts that Iran is arming, supporting and coordinating with the militia.

Despite Iran’s plans to use the Houthis as a pawn in a larger regional strategy, Israeli and American intelligence officials said the Houthis presented significant risk of miscalculation and could inadvertently incite a larger regional war that Iranian officials have said they do not want.

American officials and other experts questioned whether Iran could rein in the Houthis, who launched drones this week at a U.S. Navy destroyer, if their actions got out of control.

“This is a difficult game to fine-tune for a group like the Houthis who are not just zealots but also have very little to lose,” said Ali Vaez, the Iran director of the International Crisis Group. “There are so many points of tensions. The longer the war goes on, the bigger the risk of tensions getting completely out of control.”

On Wednesday, the U.S. Navy shot down a Houthi drone launched toward the Bab el-Mandeb Strait, a narrow entrance to the Red Sea busy with commercial ships and tankers. The Houthis also said they had fired a barrage of ballistic missiles toward Eilat, Israel.

The Houthis on Sunday launched attacks against three commercial vessels in the Red Sea. And the American destroyer, the U.S.S. Carney, shot down a Houthi drone that was heading toward it, the Navy said in a statement.

Gen. Mohammad Ali al-Ghaderi, a Houthi naval commander, said of Sunday’s strikes: “the waters of our land will become the graveyard of the Zionist enemy’s ships,” according to news media reports in Iran and Yemen.

Washington is taking the threat seriously. This week it dispatched Tim Lenderking, the special envoy for Yemen, to the Persian Gulf for consultations with regional allies on how to safeguard maritime security in the Red Sea and Gulf of Aden.

In Washington and Tel Aviv, military strategists have contemplated strikes on Yemen to contain the Houthis, two American officials and the senior Western defense official.

U.S. officials have prepared preliminary Houthi targets in Yemen in case the Biden administration orders retaliatory strikes, the two American officials said, but so far, they added, Washington does not want to risk a wider regional war. Israel has also tempered its response to attacks from Hezbollah and the Houthis, limiting its reaction when attacked and relying instead on its defenses.

Current and former U.S. military commanders said Israel’s air defenses were sophisticated enough to knock down missiles and drones launched at Israel, but the threat to international waters was a bigger challenge.

“Their ability to hurt Israel is very, very limited,” said Gen. Kenneth F. McKenzie Jr., the former head of the military’s Central Command. “The bigger risk is if they use mines or short-range cruise missiles in the Bab el-Mandeb.”

A high-ranking Israeli defense official said that if a Houthi ballistic missile were to hit Israel and cause significant damage or kill civilians, it would be extremely difficult for Israel to not respond.

In the past few years, Israel has developed strong military and intelligence cooperation with Arab countries in the Persian Gulf, including the United Arab Emirates and Bahrain, that have knowledge of Houthi targets and experience fighting them, according to military analysts.

One of the Iranian officials familiar with Iran’s planning said that the Houthis have said they would respond to any attack inside Yemen by closing the entrance to the Red Sea and indiscriminately firing a barrage of drones and missiles toward ships.