Sergei Lavrov, the Russian Foreign Minister, on Friday called the U.S. strikes “an act of aggression under a completely invented pretext.” Russia rejects the idea that Assad carried out the chemical-weapons attack, saying a Syrian air-force hit a rebel facility that manufactured chemical weapons.

“Everything resembles the situation of 2003, when the USA, the U.K., and several of their allies invaded Iraq without the UN Security Council's approval— a grave violation of international law—but at that point they at least tried to show some material evidence,” Lavrov said, referring to then Secretary of State Colin Powell’s flawed presentation to the UN Security Council that made the case for war in Iraq.

But it’s unlikely Russia will retaliate through military means. Pyotr Tolstoy, the deputy speaker of the state Duma, told lawmakers: “How can we respond? Of course not by escalating military actions … our strength is in our own understanding of the logic of events.”

Igor Konashenkov, a defense ministry spokesman, said Syrian air defenses would be bolstered following the strike “to protect the most sensitive infrastructure facilities in Syria.”

Iran, which also supports Assad and whose fighters are in Syria, condemned the strikes, as well, calling them “unilateral,” adding: “Such measures will strengthen terrorists in Syria... and will complicate the situation in Syria and the region.”

The strikes come at a delicate time because the Assad regime is engaged in a cease-fire with most moderate rebel groups—but this truce excludes ISIS and al-Qaeda-linked organizations. In fact, Assad’s chemical-weapon strike targeted Idlib province, which is controlled by an al-Qaeda-linked group. Most of the at least 70 victims were women and children.

In Syria, state media said the strike killed nine people, including four children, who lived near the airbase. In Moscow, Konashenkov said four Syrian soldiers had been also killed. He said two more were missing.

Among U.S. allies, whose diplomatic and possibly military support the U.S. will seek if there are further actions against the Assad regime, the reaction was markedly different.

In Brussels, Jens Stoltenberg, the NATO secretary-general, said the Assad regime “bears the full responsibility for this development.” He said he was informed by General James Mattis, the U.S. defense secretary, of the impending strike.

Turkey, which has been a longtime advocate of military action in Syria, urged the establishment of a no-fly zone to create Syrian safe zones for civilians. That call came from Ibrahim Kalin, a spokesman for President Recep Tayyip Erdogan.

The U.K. government, which in the past has been the most stalwart U.S. ally in military operations overseas, said it “fully supports” the strike. Michael Fallon, the U.K. defense secretary, said while Prime Minister Theresa May had been “informed” of the strike, the U.K. wasn’t asked to take part in it.