At least sixty-two Syrian troops died and 100 were wounded on Saturday when US jets bombed a Syrian government base on Al-Tharda mountain near Deir ez-Zor. Remarkably, the US Central Command has still not apologized for the attack, even though its bombing allowed the Islamic State (IS) militia to storm and capture the base shortly afterwards.

This massacre is a flagrant act of war that threatens to escalate the Syrian conflict into an all-out war pitting the US-led NATO alliance against Syria and its allies, including Russia. Everything suggests that the attack, coming in the initial days of a US-Russian ceasefire in Syria openly criticized last week by the US army brass, was deliberately committed by forces inside the US government hostile to the ceasefire.

The US military’s refusal to formally apologize for the massacre is staggeringly reckless. Syrian troops fighting US-backed Islamist opposition militias are being aided on the ground by units from Iran, China, and Russia. The Pentagon is signaling to these countries—which not only have powerful forces in Syria but, in the case of China and Russia, nuclear weapons—that their own troops may end up as targets of US military action, as they operate alongside Syrian forces.

Syrian and Russian officials denounced the bombing as US aid to IS, while Russian officials called an emergency meeting of the UN Security Council to demand explanations from Washington. The Syrian Foreign Ministry declared, “At 05:00 pm, on September 17th, 2016, five US aircraft launched a fierce airstrike on Syrian Army positions on al-Tharda Mountain in the surroundings of Deir ez-Zor Airport. The attack lasted for an hour.”

It accused Washington of complicity with IS: “The attack launched by the ISIS terrorists on the same site, taking control over it…highlights the coordination between this terrorist organization and the US.”

What emerged from the contradictory accounts of the bombing provided by the feuding factions of the US military-intelligence machine is a picture of a massacre prepared and executed in cold blood.

The Obama administration relayed regrets via Moscow to Damascus for the “unintentional loss of life of Syrian forces,” anonymous senior US officials told the press. However, the US Central Command (Centcom), responsible for the Pentagon’s operations in the Middle East, issued a perfunctory statement making no apology to the Syrian military for its losses.

“The coalition air strike was halted immediately when coalition officials were informed by Russian officials that it was possible the personnel and vehicles targeted were part of the Syrian military,” it declared, blandly adding: “Syria is a complex situation with various military forces and militias in close proximity, but coalition forces would not intentionally strike a known Syrian military unit, officials said. The coalition will review this strike and the circumstances surrounding it to see if any lessons can be learned.”

Such claims that US fighters were unaware of who they were bombing are simply not credible, and are flatly contradicted by other accounts in the media.

An anonymous Centcom official told the New York Times that US surveillance aircraft tracked the Syrian army units “for several days” before US fighters attacked them. “The attack went on for about 20 minutes, with the planes destroying the vehicles and gunning down dozens of people in the open desert, the official said. Shortly after this, an urgent call came into the American military command center in Qatar… The call was from a Russian official who said that the American planes were bombing Syrian troops and that the strike should be immediately called off.”

Nevertheless, the US jets continued to bomb the Syrian base for several minutes before ending the attack, according to the Centcom official’s account.

The attack at Deir ez-Zor shows that Washington and its allies are not seeking a cease-fire and de-escalation, let alone peace. They are pursuing the same strategy adopted by the NATO powers in Syria ever since 2011: pursuing regime change by backing Islamist militias like IS or the Al Qaeda-linked Al Nusra Front against Syrian President Bashar al-Assad’s regime. The latest attack has shown that, even after IS mounted repeated terror attacks in Europe and the United States, a definite collaboration still exists between US and IS forces to escalate the war.

After Saturday’s attack, US think tank operatives quickly came forward in the media to do political damage control. Aaron David Miller of the Wilson Center warned the Times that the air strikes would “feed conspiracy theories that Washington is in league with IS” and allow Russian President Vladimir Putin to “blast the US on the eve of the UN General Assembly.”

This is cynical propaganda. As they backed Syrian opposition militias, top US officials and journalists were fully aware of their terrorist character. Timesjournalist C. J. Chivers dedicated a friendly 2012 video to the Lions of Tawhid militia, which set off truck bombs in Syrian cities. This was only one of dozens of US-backed opposition militias that carried out atrocities across Syria, including IS, whose operations in Syria only began to be targeted last year after it carried out repeated terror attacks in Europe.

The dominant factions of the US government want war, and Moscow’s strategy—negotiating truces with Washington, and backing Assad while accommodating US military operations in Syria—is totally bankrupt. Hostile to and afraid of appealing to antiwar sentiment in the working class, particularly in the United States, the Kremlin has sought to deal with the US war drive through talks with the US government. This strategy has failed, as Russian officials were all but forced to admit, in the face of US military opposition to the cease-fire.

After the emergency meeting of the UN Security Council called by Moscow, Russian Ambassador to the UN Vitaly Churkin charged that the US attack was a deliberate attempt to derail the joint US-Russian-brokered ceasefire, pointing to the “highly suspicious” timing of the attack.

“It was quite significant and not accidental that it happened just two days before the Russian-American arrangements were supposed to come into full force,” he said. “The beginning of work of the Joint Implementation Group was supposed to be September 19. So if the US wanted to conduct an effective strike on Al Nusra or ISIS, in Deir ez-Zor or anywhere else, they could wait two more days and coordinate with our military and be sure that they are striking the right people… Instead they chose to conduct this reckless operation.”

“One has to conclude that the airstrike has been conducted in order to derail the operation of the Joint Implementation Group and actually prevent it from being set in motion,” Churkin added.

This assessment was echoed by the DEBKA File publication, which has close ties to Israeli intelligence. “The Pentagon and US army are not following the orders of their Commander-in-Chief Barack Obama in the execution of the military cooperation accord in Syria concluded by US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov in Geneva on Sept. 12,” it wrote.

It cited concerns by top US defense officials that the terms of the cease-fire give Russia too much of an “opportunity to study the combat methods and tactics practiced by the US Navy and Air force in real battlefield conditions.” For this reason, the Pentagon is opposing it even after it was agreed to by Kerry: “Washington sources report that Defense Secretary Carter maintains that he can’t act against a law enacted by Congress. He was referring to the law that prohibits all military-to-military relations with Russia as a result of Moscow’s annexation of the Crimea region of Ukraine.”