An Iranian state news outlet has denied that 18 of the country’s fighters were killed in airstrikes on Syrian army facilities.

The attack in the early hours of Monday morning is believed to have targeted a warehouse for surface-to-air missiles and Syrian government bases near the northern city of Hama and in the Aleppo countryside.

The blast at the Brigade 47 base caused secondary explosions which hit a Hama suburb sending locals running from their homes, according to opposition activist Mohammad Rasheed.

Shockwaves from the attack were so powerful it registered 2 on the Richter scale and was felt as far away as Lebanon and Turkey.

Syrian media blamed Israel, the UK and US for the strikes, calling it a “new aggression” from “enemy rockets”. It said 18 Iranians, including a commander, had been killed.

However, Iran’s state-operated Tasnim news agency quoted an unnamed government source which denied rockets had hit an Iranian base or killed any Iranian soldiers.

London-based war monitor the Syrian Observatory for Human Rights said least 26 pro-government soldiers died in the attack, mostly Iranian and Iraqi nationals.

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At least 60 people were injured and four Syrians are also believed to be among the dead, it added.

Opposition media outlets put the toll at 38 pro-regime troops dead with another 57 wounded.

Attacks on arms depots and military centres in Syria are often carried out by Israel, although the Israel Defence Forces (IDF) rarely comments on its operations inside the country.

However, it is believed to have carried out more than 100 airstrikes across the border – usually targeting Lebanese Hezbollah arms convoys – since the Syrian war began.

Iran has sent thousands of fighters to support President Bashar al-Assad’s forces in the now seven-year-old conflict.

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Iranian-allied Hezbollah as well as Shia militias from Iraq, Pakistan and Afghanistan also fight on the government’s side in the complex war.

As the Syrian conflict has evolved Israeli officials have become increasingly worried about Iran’s political influence over the Assad government.

It is believed Syria is now a potential site for missiles aimed at Israel. The presence of Iran’s Revolutionary Guards, Hezbollah and other militias so close to Israel’s borders is another source of tension.

Both Hezbollah and Iran have sworn the destruction of the Jewish state.

The latest strike comes after an attack on the Syrian T4 air base in Homs earlier this month which killed seven Iranian military personnel. Israel did not confirm or deny whether it was responsible for the attack.

On 14 April, the UK, US and France carried out a joint operation on Syrian government military research sites after an alleged chemical attack on the rebel-held suburb of Douma.