Loud explosions were reported to rock the coastal Syrian city of Latakia late Sunday night, apparently from an airstrike on the Alawite stronghold.

Citing Western sources, the Palestinian Zamnpress news website reported Monday that Israeli planes carried out the attack, targeting a warehouse of S-300 missiles.

Israeli news sources also cited Syrian opposition reports and Lebanese media reports in reporting that Israeli planes were involved in the attack.

A Syrian opposition source living in Turkey told Israel Radio that Israeli plans had attacked the site, which housed warehouses containing advanced Russian S-300 missiles.

The IDF did not respond to requests for comment and there was no independent confirmation of Israeli involvement.

According to the Local Coordination Committees in Syria, residents reported “a huge explosion” in the Shekh Daher neighborhood of Latakia.

On Sunday night, Lebanese state media reported Israeli warplanes flying over the city of Baalbek and the Bekaa Valley region.

Latakia, considered a main power center for Syrian President Bashar Assad, has been hit by airstrikes in the past, reportedly from Israeli planes.

In October 2013, a Syrian air defense base near Latakia was reportedly destroyed, with multiple Syrian and Lebanese sources speculating that an Israeli strike from the Mediterranean was to blame.

The Syrian Observatory for Human Rights at the time reported a loud explosion in a Syrian army base, and Twitter users quoted eyewitnesses who said the blast occurred near Snobar Jableh, just south of the city.

Israel has been accused of striking Syrian sites in the past, including in January and May 2013. Israel refused to confirm the reports that it targeted weapons transfers, possibly to the Lebanese terror group Hezbollah, which has remained loyal to Assad during the country’s bloody civil war.