A Russian Ilyushin Il-20 military aircraft with 14 personnel aboard disappeared over the Mediterranean Sea while returning to Hmeimim air base in Syria, media reported.

The plane went off radar while Israeli Air Force F-16 fighter jets attacked targets in Syria’s Latakia province, an official with Russia’s Defense Ministry said, Tass reported.

“On September 17, at about 11:00 [p.m.] Moscow time, the connection with the crew of the Russian Il-20 aircraft was lost over the Mediterranean Sea when the plane was returning to the airbase of Khmeimim, 35 kilometres [22 miles] from the coast of Syria,” the official said.

The ministry said the IL-20 “went off the radars disappeared [sic] during the attack of four Israeli F-16 aircraft on Syrian targets in the province of Latakia,” Tass reported.

Russia’s air base at Hmeimim launched a search and rescue operation.

The Ilyushin Il-20 is an electronic signals intelligence aircraft based on a 1950s-era turboprop-powered plane. The type first flew in 1968. It carries a wide array of antennas, optical and infrared sensors, and side-looking radar, as well as satellite communication equipment.

The Russian defense ministry said that, around the same time, “radars fixed missile launches from the French frigate Auvergne, which was in that area.”

Auvergne is an Aquitaine-class frigate or FREMM – European multi-mission frigate – which carries both surface-to-surface and surface-to-air missiles. Another FREMM, the Languedoc, launched missiles in the massive joint U.S., U.K. and France strike against Syrian chemical weapons-related sites in April.

“The French army denies any involvement in this attack,” a French army spokesperson said, The Guardian reported. French foreign minister Jean-Yves Le Drian warned on September 13 that any use of chemical weapons in Syria would “have the same consequences as we knew in April.”

Syria’s state-run SANA news agency reported a military source as saying that Syrian Arab Army air defense units had “responded to hostile missiles coming from the sea view towards the city of Latakia and intercepted a number of them before reaching their goals.”

It said that the missiles targeted the Technical Industries Corporation.

Syria’s state-run Al-Ikhbariya TV said 10 people were injured in the strikes, AP reported. A similar attack on Damascus International Airport on September 15 was also blamed on Israel, as were strikes in the Tartus and Hama areas on September 4.

A Pentagon spokesperson told The Defense Post: “The missiles were not fired by the U.S. military and we have nothing further at this time.”

However, CNN reported an unnamed U.S. official as saying that the U.S. military believes the aircraft was hit by Syrian anti-aircraft fire that was targeting Israeli missiles. A second unnamed U.S. official also said that Israel had fired missiles at targets in Syria.

A U.S. official told Reuters that the U.S. government’s working theory was that Syrian air defenses shot down the Russian plane while firing at Israeli missiles.

Israel does not comment on strikes it carries out in Syria, although an Israeli military official said earlier this month that it has struck over 200 targets in Syria over the past 18 months, AP reported.

When asked about both the reported Israeli missile strike and the Russian aircraft disappearance, an Israeli military spokesperson said: “We don’t comment on foreign reports,” AFP reported.

This post was updated on September 18, 2018 and edited for clarity.