An attack by drones loaded with explosives against a Saudi oil facility is the second such attack this week.

Saudi Energy Minister Khalid al-Falih announced on Tuesday that two oil pumping stations for the East-West pipeline had been hit by explosive-laden drones.

Al Masirah television, a Yemeni TV channel based in Beirut that is affiliated with the Iran-backed Houthi rebels, claimed that the Houthis had carried out a “major operation” against Saudi Arabia. The report was picked up by Iran’s Tasnim news and also by Press TV. The Masirah TV report cited a Houthi military official as saying that “seven drones carried out attacks on vital Saudi installations.”

On Twitter, Al Masirah cited the official as saying, “This large military operation is in response to the continued aggression and blockade of our people and we are prepared to carry out more unique and harsh strikes.”

This drone attack comes just two days after four oil tankers including two Saudi tankers were targeted by “sabotage attacks” off the coast of the United Arab Emirates. It is suspected that the attack against the oil tankers was connected with Iran. Tensions are high as the White House ordered the USS Abraham Lincoln aircraft carrier strike group and B-52 bombers to the region on May 4, to counter “clear indications” of threats from Iran to American forces in the region.

The New York Times reported on Monday that a top U.S. defense official presented an updated military plan to President Donald Trump’s senior security aides that included dispatching up to 120,000 troops to the region should Iran attack American interests or escalate work on nuclear weapons.