A burst of deadly violence between U.S. forces and suspected Iranian proxies in Syria has reignited long smoldering tensions between Washington and Tehran, with the Biden administration warning Friday that while it wants to avoid a wider confrontation, indiscriminate attacks on U.S. troops would not go unpunished."The United States does not - emphasize does not - seek conflict with Iran," President 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."At the Pentagon, Brig. Gen. Patrick Ryder, a spokesman, told reporters 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 bloodshed began Thursday when a self-detonating drone struck a U.S. facility in northeast Syria. 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 the Middle East on and off for years.Hours later, Ryder said, 10 rockets were launched at Green Village, a U.S. military position about 100 miles south in Syria. The Pentagon also linked those attacks to militias backed by Iran. It said there were no injuries to U.S. or coalition personnel, and no damage to U.S. equipment.The violence underscored what Gen. Michael "Erik" Kurilla, the top U.S. military officer overseeing operations in the Middle East, described on Capitol Hill this week as an escalating series of incidents targeting U.S. personnel in the region by groups with ties to Iran. He told members of the House Armed Services Committee that Iranian-backed forces had launched 78 such attacks since January 2021, 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 the wounded were rushed to a medical facility in Iraq, officials said. All were in stable condition early 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. Ryder said that the incident is under review.The Deir Ezzor 24 activist group, which has sources in the area where 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.Biden consulted with his national security team before authorizing the airstrikes, White House spokesman John Kirby told CNN on Friday morning. The president decided to act "very, very shortly" after receiving recommendations from senior defense leaders and the intelligence community, Kirby said.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."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 across the border in Iraq.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 his House testimony 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.- - -The Washington Post's Louisa Loveluck in London contributed to this report.

A nine-minute Fox News appearance last year has earned Sen. Lindsey O. Graham (R-S.C.) a public admonishment from the Senate Ethics Committee because, during it, he solicited campaign contributions for former Georgia Senate candidate Herschel Walker while standing on Capitol grounds.