By Dan Lamothe and Missy Ryan

The president said that while the U.S. wants to avoid a wider confrontation, indiscriminate attacks on U.S. troops would be met with force

A burst of deadly violence between U.S. forces and suspected Iranian proxies in Syria has reignited long smoldering tensions between Washington and Tehran, as President Biden warned Iran on Friday that violent attacks on American troops would be met with retribution.

“The United States does not — emphasize does not — seek conflict with Iran,” Biden, speaking in Ottawa alongside Canadian Prime Minister Justin Trudeau, said after U.S. warplanes carried out retaliatory airstrikes for the death of an American contractor. “But be prepared for us to act forcefully to protect our people. That’s exactly what happened last night.”

Defense Department spokesman Brig. Gen. Patrick Ryder told reporters at the Pentagon that the operation, conducted overnight at Biden’s direction, was intended “to send a very clear message that we will take the protection of our personnel seriously, and that we will respond quickly and decisively if they are threatened.”

The violence that erupted in Syria in recent days highlights the risk for escalation at a moment when Washington and Tehran remain sharply at odds over issues including Iran’s nuclear program, the country’s support for militants across the Middle East and, since last year, its provision of military technology to Russia for its war in Ukraine.

The president’s remarks underscored his attempt to avoid further violence while also containing attacks by proxy forces that have long posed a threat to Americans in Iraq, Lebanon and beyond.

The bloodshed began Thursday when a self-detonating drone struck a U.S. facility in northeast Syria, where hundreds of American troops remain stationed in a counterterrorism mission begun years ago to dismantle the Islamic State.

Beyond the contractor’s death, five U.S. troops and a second contractor were wounded in the attack, which Biden administration officials promptly linked to militias trained and armed by Tehran.

American F-15 fighter jets carried out two airstrikes in response, Ryder said. The jets targeted facilities associated with the Islamic Revolutionary Guard Corps, an elite Iranian force that, via its network of proxies, has targeted U.S. troops in Syria on and off.

Hours later, Ryder said, 10 rockets were launched at Green Village, a U.S. military position about 100 miles south of Thursday’s assault. The Pentagon also linked those attacks to militias backed by Iran but said there were no injuries to U.S. or coalition personnel nor any damage to U.S. equipment.

The incidents occur as Saudi Arabia, a central American partner in the Middle East, begins what could mark a dramatic rapprochement with Iran. The tentative agreement to resume diplomatic relations after years of antagonism, under a deal brokered this month by China, underscores Beijing’s expanding clout across the Middle East as America refocuses on what officials view as larger threats from Russia and China.

While the United States retains a large military footprint across the region, U.S. leaders are hoping to avoid the long, costly combat missions that dominated American foreign policy in the decades after 9/11.

Speaking to lawmakers this week, Gen. Michael “Erik” Kurilla, the top U.S. military officer overseeing operations in the Middle East, said that, since January 2021, groups with ties to Iran had launched 78 attacks targeting U.S. personnel in the region, a higher number than previously disclosed.

Thursday’s drone attack occurred outside the northeastern city of Hasakah, where thousands of Islamic State fighters have been detained following the collapse of their self-declared caliphate over the last decade. Some of those wounded were rushed to a medical facility in Iraq, officials said. All were in stable condition on Friday.

None of the victims has been identified. The New York Times reported Friday that the facility’s air defenses were not fully operational when the attack occurred. The incident would be reviewed internally, Ryder said, and officials planned to examine what additional “mitigating actions” may be necessary to ensure American personnel are protected against possible future attacks. He declined to elaborate.

The Deir Ezzor 24 activist group, which has sources in the area where the airstrikes occurred, said that four members of what it described as Iranian-linked militias were killed near the town of Deir al-Zour, and that others, including Iraqi citizens, were wounded. The Syrian Observatory for Human Rights, a British group that documents violence in the region, said 11 people died in the airstrikes. Ryder said Friday that the Pentagon continues to assess casualties resulting from the operation.

President Biden gestures during a joint press conference with Justin Trudeau, Canada's prime minister, in Ottawa on Friday. (David Kawai/Bloomberg News)

Biden consulted with his national security team before authorizing the airstrikes, White House spokesman John Kirby told CNN on Friday. The president decided to act “very, very shortly” after receiving recommendations from senior defense leaders and the intelligence community, Kirby said.

The violence underscores the ongoing instability in Syria, where, 12 years after the start of its civil war, the country is a patchwork of areas controlled by the government of President Bashar al-Assad, Kurdish and other forces. Assad’s government is supported by Russia and Iran.

About 900 American personnel, bolstered by hundreds of contractors, are based in Syria where they are partnered with the Syrian Democratic Forces, a Kurdish-led group. Another 2,500 U.S. troops are located in Iraq.

Kirby characterized the region where Thursday’s attack occurred as “dangerous,” and said American personnel assigned there are focused principally on ensuring “the enduring the defeat” of the Islamic State. “We’ve been very clear with the Iranians and with our partners about how serious the mission that we’re doing in Syria is and how much we’re going to protect that mission,” Kirby said. “Iran should not be involved in supporting these attacks on our facilities and on our people.”

Kurilla told lawmakers that Tehran now possesses the largest and most diverse missile arsenal in the Middle East, and the largest and most capable unmanned aerial vehicle force in the region.

“The advancement of Iranian military capabilities over the past 40 years is unparalleled in the region; in fact, the Islamic Revolutionary Guard Corps of today is unrecognizable from just five years ago,” he said in testimony to the House of Representatives Thursday.

In a statement released after the airstrikes, the general said that the United States has “scalable options” should tensions with Iran or it proxy forces escalate further.

Thursday’s violence marks the latest flash point as Iran and its supporters work to force the United States from the region.

In 2018, President Donald Trump’s decision to withdraw the United States from a landmark nuclear deal with Tehran sparked rounds of violence in Iraq, as well.

When Iranian-linked militias fired volleys of rockets into the U.S. Embassy in Baghdad and targeted coalition bases around the country, killing and wounding Iraqi and foreign troops, Trump responded by ordering the killing of a leading Iranian general, Qasem Soleimani, and authorizing airstrikes on militia groups in Iraq and Syria.

Iran retaliated by firing ballistic missiles at U.S. military positions, with 11 detonating at Ain al-Asad Air Base in western Iraq. The explosions destroyed aircraft and buildings and left craters on the base, with more than 100 U.S. troops suffering traumatic brain injuries.

Tensions have ebbed in recent months, but the attacks remain a significant concern for the U.S.-led coalition.

Louisa Loveluck in London contributed to this report.

By Dan LamotheDan Lamothe joined The Washington Post in 2014 to cover the U.S. military. He has written about the Armed Forces for 15 years, traveling extensively, embedding with each service and covering combat in Afghanistan. His reporting about the 2021 attack on the Capitol was part of a project that earned the 2022 Pulitzer Prize for Public Service. Twitter

By Missy RyanMissy Ryan writes about diplomacy, national security and the State Department for The Washington Post. She joined The Post in 2014 to write about the Pentagon and military issues. She has reported from Iraq, Egypt, Libya, Lebanon, Yemen, Afghanistan, Pakistan, Mexico, Peru, Argentina and Chile. Twitter