An Israeli strike on the Syrian capital has destroyed a building used by the Iranian paramilitary Revolutionary Guard, killing at least five Iranians, Syrian and Iranian state media reported.

The Syrian army said the building in the tightly-guarded western Damascus area of Mazzeh was entirely destroyed, adding that the Israeli air force fired the missiles while flying over Syria’s Israeli-occupied Golan Heights.

A few hours later, an Israeli drone strike on a car near the southern Lebanese port city of Tyre killed two Hezbollah members, an official with the group said.

One of those killed was Ali Hudruj, a local Hezbollah commander.

Nour News, which is believed to be close to the country’s intelligence apparatus, identified two of the dead in Damascus as Gen Sadegh Omidzadeh, the intelligence deputy of the guard’s expeditionary Quds Force in Syria, and his deputy, who goes by the nom de guerre Hajj Gholam.

The guard later issued a statement identifying the dead as Hojjatollah Omidvar, Ali Aghazadeh, Hossein Mohammadi and Saeed Karimi. It gave no ranks for them. The difference in information could not be immediately reconciled.

An opposition war monitor, the Syrian Observatory for Human Rights, said at least six people – five Iranians and a Syrian – were killed in the missile attack that struck while officials from Iran-backed groups were holding a meeting.

The Observatory’s chief, Rami Abdurrahman, said three of the Iranians were commanders, adding that four other people are still missing under the rubble.

Iranian Foreign Ministry spokesman Nasser Kanaani condemned the Israeli strike in a statement, saying that “without any doubt, the blood of these high-ranking martyrs will not be wasted”.

He added that Tehran “reserves its right to respond to the organised terrorism of the fake Zionist regime at the appropriate time and place”.

Iran also tried again to link Israel to the so-called Islamic State group, something its leaders have been trying to do since a suicide bombing by the extremists in early January in Iran killed more than 90 people.

Syrian state TV reported that the “Israeli aggression” targeted a residential building in Mazzeh, home to several diplomatic missions. Saturday’s strike was close to the embassies of Venezuela and South Africa.

An official said that the building was used by Revolutionary Guard officials, adding that the “Israeli missiles” destroyed the whole building and that 10 people were either killed or wounded in the attack.

The Israeli military did not comment on the strike.

Security forces deployed around the destroyed four-storey building as ambulances and fire engines were seen in the area. A search for people trapped under the rubble is under way. Windows were also shattered in nearby buildings.

A grocer near the scene of the strike said he heard five consecutive explosions at about 9.15am (6.15am GMT), adding that he later witnessed the bodies of a man and a woman being taken away as well as three injured people.

The strike came amid widening tensions in the region as Israel pushes ahead with its offensive in Gaza.

The war has stoked tensions across the region, threatening to ignite other conflicts.

Last month, an Israeli air strike on a suburb of Damascus killed Iranian general Seyed Razi Mousavi, an adviser of the Iranian paramilitary Revolutionary Guard in Syria. Israel has also targeted Palestinian and Lebanese operatives in Syria over the past years.

Iranian and Syrian officials have long acknowledged Iran has advisers and military experts in Syria, but denied there were any ground troops. Thousands of fighters from Iran-backed groups took part in Syria’s conflict that started in March 2011, helping tip the balance of power in favour of President Bashar Assad.

Israel has carried out hundreds of strikes on targets inside government-controlled parts of war-torn Syria in recent years.

Such actions in Syria are rarely acknowledged by Israel, but it has said that it targets bases of Iran-allied militant groups, such as Lebanon’s Hezbollah, which has sent thousands of fighters to support Syrian President Bashar Assad’s forces.

Earlier this month, a strike said to be carried out by Israel killed top Hamas commander Saleh Arouri in Beirut.

Over the past weeks, rockets have been fired from Syria into northern Israel and the Israeli-occupied Golan Heights, adding to tensions along the Lebanon-Israel border and attacks on ships in the Red Sea by Yemen’s Iran-backed Houthi rebels.