Missiles struck an air base in central Syria early today, but the Pentagon quickly denied claims from Syrian state media that the strikes were “an American aggression.” A war-monitoring group said Iranian-backed militia members were killed in the strikes, and Russia and then Syria accused Israeli jets of firing the missiles.

Syria’s state-run SANA news agency said the missile attack on the T4 military air base in Homs province had resulted in a number of casualties. The London-based Syrian Observatory for Human Rights (SOHR) said 14 people were killed, including foreign nationals, an allusion to Iranian, or at least Iran-backed, fighters.

Russia’s allegation that two Israeli F-15s had fired a total of eight missiles at the T4 base came several hours after Pentagon spokesman Christopher Sherwood said in a statement that the “Department of Defense is not conducting air strikes in Syria.”

The missile attack followed a suspected poison gas attack Saturday on the last remaining foothold for the Syrian opposition in the eastern suburbs of Damascus. At least 40 people were killed, including families found in their homes and shelters, opposition activists and local rescuers said.

Videos from Douma show lifeless bodies with no visible injuries, all of them apparently inside buildings, survivors struggling to breathe, many of them children. Victims are seen being washed down, apparently to remove a substance from their skin.

President Trump has promised a “big price to pay” for the suspected chemical attack and called Syrian President Bashar Assad an “animal” in tweets sent earlier Sunday.

Survivors, though, reportedly smelled of chlorine, a chemical that can be deadly in confined spaces.

Dr. Ahmad Tarakji, of the Syrian American Medical Society, said that at his field hospital in eastern Ghouta, they “received many patients who suffered from symptoms compatible with exposure to chlorine gas – high concentration chlorine gas.”

On Monday, Russian Foreign Minister Sergey Lavrov called the accusations against Bashar Assad’s regime a “provocation” and, referring to the airstrikes on the base in Homs, he added that the situation in Syria was, “becoming too dangerous” as “actors whom nobody invited” show up on the complex battlefield.

Israel’s government did not confirm that it had carried out any strikes in Syria, but it has targeted Assad’s forces, and their Iranian allies, inside the country before. Some Israeli media noted.

Russia’s Ministry of Defense said Monday that “two F-15 aircraft of the Israeli Air Force, without entering Syrian airspace, struck eight controlled missiles at the airfield.” It said the missiles were fired from within Lebanese airspace, and that five of them were destroyed by Syria’s air defenses before landing.

Three missiles “reached the western part of the airfield,” according to the Russian military, which also has personnel in the area in support of Assad’s forces. No Russian “advisers” were hit in the early morning missile strike, according to Russia.