RIYADH, Saudi Arabia: Saudi Arabia has launched a military offensive against Iran-backed Houthi forces in Yemen, with plans ranging from a limited push to retake the Bab el-Mandeb shipping route to a wider attack on several fronts, regional and Western officials told Reuters.

The operation has just begun and is being led by Yemeni forces overseen by Riyadh, with support from Saudi air strikes, according to six people familiar with the preparations.

The United States is already providing intelligence to support Saudi operations in Yemen. Some regional and European countries are also giving Saudi Arabia mainly defensive military assistance. However, these allies are not expected to take part directly in combat, the officials said. They spoke anonymously because of the sensitivity of the security plans.

Saudi Arabia entered Yemen's civil war in 2015 at the head of an Arab coalition supporting the internationally recognized government. The Houthis had driven that government from the capital, Sanaa.

A truce between the two sides agreed in 2022 largely held until this year, when the Houthis began missile and drone attacks on Saudi shipping and oil infrastructure as the conflict with Iran spread across the region.

A major aim of the planned offensive is to reverse recent Houthi gains along the Yemeni coast. The group advanced south last month and seized control of the Bab el-Mandeb strait, according to Gulf and Yemeni officials and Western diplomats familiar with the plans.

Saudi Arabia is considering its strategy, the officials said. One is for a limited operation around Bab el-Mandeb. The other is for a wider offensive involving coordinated attacks on several fronts in Al-Bayda, Marib, Taiz and Al-Jawf governorates.

Depending on the size of the operation, officials said more than 100,000 Yemeni troops could be mobilized.

Bab el-Mandeb is the southern gateway to the Red Sea and an important shipping route linking the Mediterranean with Asia. Its importance has increased this year because the Iran-linked conflict has effectively closed the Strait of Hormuz.

Saudi Arabia has concluded that it cannot enter new peace talks with the Houthis while the group controls Bab el-Mandeb, according to Western diplomats and a Middle East official. Control of the strait gives the Houthis significant influence over international shipping.

The six people familiar with the preparations said their estimates ranged from within a week to after the U.S. midterm elections in early November.

The Houthis have emerged as Iran's strongest regional ally since Israel weakened Hezbollah in Lebanon over the past three years.

The Saudi-led offensive adds another major flashpoint to a region that has been affected by conflict since the Hamas-led attacks on Israel on October 7, 2023, followed by the U.S.-Israeli war with Iran.

The United States, Saudi Arabia's most powerful ally, is providing military advisers and intelligence, including information used for targeting, to support Saudi air operations in Yemen, according to a Western diplomat.

Pakistani military advisers are also in Saudi Arabia working with Saudi counterparts to support Yemeni forces, according to a Pakistani official, a Middle East official and a Western diplomat. Turkish drones purchased by Saudi Arabia before the current war have also been deployed over Yemen, they said.

A major concern for Saudi Arabia is protecting its oil facilities and other critical infrastructure from possible Houthi missile and drone attacks during a new offensive.

France has also announced plans to send defensive systems and troops to Saudi Arabia to help protect the Red Sea port city of Yanbu.