Houthi attacks on Saudi oil depots along the Red Sea on Sunday led to a drop in ship traffic through the Bab el-Mandeb Strait, according to the analytics platform Kpler on Monday.

The strait saw 11 cargo vessels move through the strait, the lowest number of ships to pass through in months, according to Kpler’s data.

Three of the seven oil vessels entered the Red Sea, while two were headed to the Saudi port of Yanbu to load Saudi crude, the data showed. Another vessel was a Russian-linked ship, while four others carrying 2 million barrels of Saudi and Emirati crude included a Hong Kong-flagged very large crude carrier. Another tanker carried around 750,000 barrels of Saudi crude headed for Pakistan.

A Houthi-led blockade in the Red Sea has disrupted commercial traffic to hurt U.S. partners in the Persian Gulf as a result of the U.S.-Israeli conflict in Iran. The blockade was imposed last week in response to a strike on Sanaa International Airport in northern Yemen, though the Saudi-backed Yemeni government claimed responsibility for the strike.

The Houthis, a Yemeni militant group deemed by the Trump administration to be a foreign terrorist organization, are backed by Iran’s regime.

On Saturday, Houthi spokesperson Brig. Gen. Yahya Saree said the militant group fired missiles and drones toward Saudi Arabia “in response to this blatant and criminal aggression.”

“Both operations successfully achieved their objectives thanks to Allah Almighty, with accurate and direct strikes,” Saree said in a statement posted to social media.

As of Monday, international benchmark Brent crude oil dipped to more than $90 a barrel, having jumped to around $101 a barrel Thursday. West Texas Intermediate, the North American benchmark, dropped to more than $83 a barrel.

Around 8 percent of the world’s oil passes through the Bab el-Mandeb Strait at the Red Sea’s southern end, according to the U.S. Energy Information Administration. Two-thirds of the roughly 6.2 million barrels of oil that have passed through the strait over the last two months originated from Saudi Arabia, bypassing the closed-off Strait of Hormuz, where around 20 percent of the world’s oil is exported.

Kpler’s data also showed that seven vessels, including three Iranian-linked oil tankers, passed through the Strait of Hormuz on Sunday.

President Trump warned against the Houthi attacks, saying he would blame them on Iran and hold the regime responsible. The U.S. and Iran have paused firing at each other after nearly two weeks of U.S. strikes on Iranian infrastructure.