After failing to talk the US out of bombing targets in Syria, Russia responded to Friday’s strikes by saying they “threatened” Russia and warning of “consequences.”

“Our warnings have been left unheard,” Russia’s ambassador to the US, Anatoly Antonov, said in a tweet on Saturday morning. “We are being threatened. We warned that such actions will not be left without consequences.”

The US, UK, and France hit three targets in the Damascus suburbs around 9 pm Eastern on Friday using aircraft and cruise missiles launched from ships. All three targets were connected to Syria’s chemical weapons program, according to Department of Defense spokesperson Dana White.

Yet according to the Defense Department, though Russian radar systems in Syria were on and detected US warplanes planes, Russia chose not to fire on them, instead only attempting to shoot down some of the cruise missiles. This suggests that despite Russia’s warnings of dire consequences, it appears Russian commanders are being extremely careful not to respond in a way that could escalate tensions with the US into a shooting war.

The strikes were a response to the Syrian regime’s use of chemical weapons on April 7 in Douma, Syria, that killed 42 civilians — many of them children — and wounded more than 500 others. President Donald Trump immediately said Syrian President Bashar al-Assad would pay a “big price” and blamed both Russia and Iran for supporting the Assad regime.

It’s the second time Trump has authorized bombing targets in Syria after a chemical attack. In April 2017, the US struck an airbase in Syria using cruise missiles. Human rights groups have reported a number of other chemical attacks, but until Saturday Trump hadn’t responded with military force again.

Iran also issued strong statements early Saturday condemning the strikes. Iran’s Supreme Leader Ayatollah Ali Khamenei tweeted that the leaders of the US, UK, and France “committed a major crime” with the strikes and proceeded to blame the US for helping to create ISIS and unleashing it on Iraq and Syria.

The U.S. played a major role in creating #ISIS, they entered where ISIS was trapped to save them. They raised the wicked creatures [ISIS] with Saudi money, turning them [ISIS] lose on Iraqi and Syrian nations; but, resistance against the US and their agents saved these countries. — Khamenei.ir (@khamenei_ir) April 14, 2018

Russian President Vladimir Putin also called for an immediate emergency meeting of the UN Security Council to discuss the “aggressive actions” of the US, UK, and France.

At the council meeting Saturday morning, Russia’s ambassador to the UN Vasily Nebenzya said that the bombing “makes an already catastrophic humanitarian situation in Syria even worse.”

US Ambassador to the UN Nikki Haley responded, saying she’d spoken with Trump hours earlier and he’d told her, “If the Syrian regime uses this poisonous gas again, the United States is locked and loaded.”

Russia defends Assad but avoids direct confrontation with the US

Experts and lawmakers warned before the strikes that although the chance is small, bombing Syria could increase the odds of a war between Russia and the US.

“The possibility of an open conflict with Russia is not zero, and any time it’s not zero we need to be careful,” Sen. Martin Heinrich (D-NM) told me on Thursday.

Russia continues to back Syrian President al-Assad, providing military equipment, including air-defense systems, and has sent Russian troops and paid Russian mercenaries to Syria. But Russian President Putin issued a statement on Saturday accusing the US of making “the already catastrophic humanitarian situation in Syria even worse and bring[ing] suffering to civilians” with its strikes. Yet he made no mention of a possible Russian military response.

Putin also denied that the Assad regime used chemical weapons in Douma, saying Russian military experts had tested the area and found nothing. US officials have said they have blood tests from civilians in Douma that prove the Assad regime used chemical weapons.

Alex Ward contributed reporting to this article.