AMMAN/CAIRO (Reuters) - Syria accused Israel on Monday of carrying out overnight missile strikes on a major airfield, after earlier saying it suspected the United States of being behind the attack.

Russia, the Damascus government’s key ally, also said two Israeli F-15 war planes carried out the strikes near Homs in central Syria. An Israeli military spokesman said he had no immediate comment.

Russia’s Defence Ministry said Israel conducted the strikes from Lebanese air space, and Syrian air defense systems shot down five out of eight missiles, the Interfax news agency reported.

“The Israeli aggression on the T4 airfield was carried out with F-15 planes,” the Syrian state agency SANA said, citing a military source.

Washington has denied launching any air strikes against the country. France was not involved in the strikes, a defense ministry official said.

Israel has previously accused Damascus of allowing Iran to set up a complex at the base to supply arms to its ally, Lebanon’s Shi’ite Hezbollah.

Monday’s statements were unusual for Russia, which has generally been reticent about Israeli strikes in Syria even as it tries to shore up President Bashar al-Assad’s rule.

Russia and Israel set up a hotline in 2015 to prevent accidental clashes between their forces in Syria, and diplomatic sources on both sides say Moscow is willing to turn a blind eye to Israeli actions as long as they do not destabilise Damascus.

Israel rarely acknowledges strikes in Syria but has said that, as a matter of policy, they aim to thwart the entrenchment of Iranian forces or arms transfers to Hezbollah.

U.S. President Donald Trump said on Sunday there would be a “big price to pay” after medical aid groups reported dozens of civilians, including many children and women, were killed by poison gas in a besieged rebel town.

The United States launched a cruise missile strike on a Syrian air base a year ago, after dozens of civilians died in a gas attack in an opposition town in northwest Syria.

The Syrian state has denied that government forces launched any chemical attack. Russia, Assad’s most powerful ally, has called the reports fake.