Shaddadi, Syria — Last week’s fatal collision between U.S. and Russian proxy forces in Syria has many ominous portents. But to hear the Syrian Kurdish commander who was overseeing the battle describe it, this is above all a tale of Russian bad faith, which U.S. officials see as a chronic problem in resolving the Syrian war.

Gen. Hassan, the commander of the Kurdish-led Syrian Democratic Forces in this region, points to a spot on the map just east of Deir al-Zour, about 50 miles southwest of here, where he says tanks and artillery backing the regime of President Bashar Assad began advancing Wednesday night toward the headquarters occupied by his forces and their advisers from U.S. Special Operations forces. (Hassan, like some other senior Kurdish commanders, didn’t give his full name.)

Hassan says he had intelligence reports that the pro-regime attack was coming. So at 9:30 Wednesday night, about a half-hour before the assault began, he called his regular Russian liaison contact in Deir al-Zour — hoping to avoid a battle.

“We told them there is some movement, and we don’t like to … attack on this movement. They [the Russians] don’t accept our offer and denied, said there’s nothing happening,” Hassan said through an interpreter. He was speaking to several reporters who traveled here Thursday with Maj. Gen. James B. Jarrard, who oversees U.S. Special Operations forces in Syria and Iraq.

U.S. commanders attempted a similar de-confliction. According to a Pentagon statement Thursday, “Coalition officials were in regular communication with Russian counterparts before, during and after” the attack. “Russian officials assured coalition officials they would not engage coalition forces in the vicinity,” the statement said.

The attack began about 10 p.m., Hassan said, with pro-regime advancing troops under a volley of tank and artillery shells that landed about 500 yards from the positions occupied by the SDF and the American soldiers. Hassan said the ground-attack force included some Russians, who he believed were mercenaries. (Russia officially doesn’t have ground troops fighting here.)

U.S. airpower responded to this threat to American troops with devastating firepower, from AC-130 ground-attack planes to armed drones. The Pentagon estimated that more than 100 were killed. Hassan indicated that the casualties included some Russians, apparently from the mercenaries fighting alongside pro-regime forces. The United States suffered no casualties, and the SDF had one wounded.

Hassan said that as the carnage spread, the Russian liaison officer contacted him again, asking for a pause to collect the dead and wounded — from an attack he had earlier denied was coming. The Kurdish commander saw this as a breach of faith.

“We don’t trust Russia anymore,” Hassan said. When a reporter asked about the irony of the Russian officer denying the attack and then asking for a truce, Hassan responded: “It’s funny that a superpower doesn’t know what their forces are conducting on the ground.” The pro-regime forces mounted their attack this week, he says, because “the regime thinks we are weak,” as the SDF has moved fighters north to fight a Turkish attack on the Kurdish region called Afrin.

The rout ended at about 5:30 a.m. When we arrived about seven hours later, the Kurdish commander was still flush with victory. He took us on a tour later of the SDF’s front-line positions against scattered Islamic State remnants east of Shaddadi.

How to add up the balance sheet? The U.S. military showed its overwhelming military dominance in the areas it controls in eastern Syria. Russian-backed forces paid dearly for their unprovoked and, it seems, deceitful attack. But the incident also demonstrated the fragility of the U.S. role in Syria, politically and diplomatically.

It matters in understanding this event that the base the pro-regime force attacked is near an oil- and gas-rich field known as Conoco, after its former American owner. The SDF seized it from the Islamic State last September and has been guarding it ever since.

The Wall Street Journal reported last Sept. 25, just after the Kurds initially seized the area, that they wanted it as “a bargaining chip.” An SDF commander told the Journal back then: “Our goal is to prevent the regime from taking the areas of oil which will enable it to regain control of the country like it was before.”

The Russian Defense Ministry issued a lame statement Thursday, claiming that the attackers were chasing Islamic State fighters. That’s nonsense, as the Russians surely knew. There are no Islamic State fighters left in that area, thanks to the U.S.-led coalition. So what’s the United States doing there now? The Russian statement made a telling argument that the U.S. military is “taking control of the country’s economic assets,” not just fighting terrorists.

Score one for American military power against Russia’s tactic of operating through deniable “Little Green Men.” But there’s no plus for the larger American mission. This incident only underlines the precariousness of the United States’ long-term role in Syria.

— David Ignatius is a columnist for Washington Post Writers Group.