In the hours before the United States carried out strikes against Iranian-backed militants on Friday, Washington attacked Tehran with more familiar weapons: sanctions and criminal charges.

The Biden administration sanctioned officers and officials of the Islamic Revolutionary Guard Corps, Iran’s main military force, for threatening the integrity of water companies and for helping to manufacture Iranian drones. And he revealed charges against nine people for selling oil to finance militant groups Hamas and Hezbollah.

The timing seemed designed to put pressure on the Revolutionary Guard and its most elite unit, the Quds Force, at a time of extraordinary tension in the Middle East. Although the sanctions have been in the works for some time and the charges were previously filed under seal, the region has been in turmoil for months.

The actions are part of a coordinated government-wide effort to thwart Iran’s attempts to use illicit oil sales to finance terrorism and roll back the country’s increasingly capable offensive cyber operations. In the 15 years since the United States launched a major cyberattack on Iran’s nuclear facilities, the country has trained a generation of hackers and struck back against Israel, Saudi Arabia and the United States, among others.

The effects of sanctions and accusations are difficult to measure. Few Iranian officials or officials hold assets in Western banks or travel to the United States, meaning the sanctions may have little practical effect. While the indictments and sanctions have a psychological element, demonstrating to Iranians and their business partners around the world that Western intelligence agencies often track their movements and transactions, actual arrests and trials are rare.

“The reason we bring these cases is that we know that the money Iran makes from the illicit sale of oil is used to finance its malign activities around the world,” Matthew G. Olsen, who heads the national security division of the Justice Department. , he said on Friday. “The threats posed by Iran and the destabilizing effects of its actions have only become more evident since the attacks of October 7,” the day of the Hamas attack on Israel that killed approximately 1,200 people.

There have been a series of actions against Iran in the past week, culminating in Friday’s attacks on Iranian proxies in Syria and Iraq. The airstrikes were in retaliation for a drone strike last Sunday that killed three US service members at a base in Jordan.

On Monday, the Justice Department unsealed charges in Minnesota against an Iranian accused of hiring a member of the Hells Angels to kill Iranian dissidents living in Maryland. On Wednesday, four Chinese nationals were charged in Washingtonaccused of attempting to smuggle and export technology used in military equipment and weapons to groups associated with the Revolutionary Guard, part of an ongoing effort to evade the West’s numerous bans on the sale of technology that could be used in weapons or surveillance systems.

Sanctions related to water companies involved attacks on so-called “logic controllers,” which are made by an Israeli company, Unitronics, and operate pumps and valves in water systems. Reaching out to controllers is a way to remind the United States and other countries that their critical infrastructure is vulnerable.

“The United States, in coordination with the private sector and other affected countries, quickly remediated the incidents with minimal impacts,” the Treasury Department said. But it wasn’t the only such attack to come from Iran: Ransomware attacks have emanated from Iranian hackers, including one against Boston Children’s Hospital three years ago, and even against a major Las Vegas casino.

The sanctions were against a number of officials from the Revolutionary Guard’s “electronic warfare and cyber defense organization,” including its leader, Hamid Reza Lashgarian.

Another set of sanctions, issued by the State Department, targeted four companies that the United States said supplied materials and technology to Iran’s missile and drone programs. Drones have been of particular concern because Russia is using them in large numbers against Ukraine.

The most sweeping move came from the Justice Department, which unveiled charges against nine people from Iran, Turkey, China and Oman related to efforts to smuggle and sell Iranian oil in violation of U.S. laws.

The legal action came as tensions between the United States and Iran deepen. Attacks like the one that killed three Americans are financed by illicit sales of Iranian oil, officials said. And the intensity has increased since October 7, with more than 160 attacks against US military forces in Iraq, Syria and Jordan by Iranian-backed militias.

“Today’s cases are part of the department’s ongoing efforts to cut off the flow of black market Iranian oil that funds the regime’s malign activity, threatening the United States and our interests around the world,” Olsen said.

Eric Schmitt contributed reporting from Washington.