Earlier in the day, Iran's FARS news agency reported that at least four Iranian nationals had been killed in an Israeli airstrike on Syria's N-4 airbase in the country's Homs province.
"I do not know what happened there or who attacked", Liberman said, adding: "I know one thing for certain - we won't allow Iran to establish itself in Syria, whatever the cost".
Syria and its main ally Russian Federation blamed Israel for carrying out the attack.
Shi'ite-dominated Iran is Assad's main regional ally and has provided military and economic support for his conflict with a range of Sunni Muslim rebel and militant groups.
Tehran, which usually remains mum about Israeli strikes harming its assets in Syria, acknowledged - through its semi-official media outlets - that Iranians were killed by Israel's warplanes, and vowed revenge.
"The Zionist regime and the United States have in different stages rushed to the scene to boost the morale of terrorists", he said, according to Iran's Press TV.
Syria responded to Trump's threats by evacuating airports and military airbases, the Syrian Observatory for Human Rights said.
Russian Federation has warned that USA strikes in Syria would have "grave consequences", according to a Foreign Ministry statement.
The Jewish state has carried out attacks in Syria, alleging that its longtime enemy Iran is building military bases there.
"The timing of the strike isn't coincidental", he said. While Assad and his allies deny perpetrating chemical weapons attacks, the worldwide community continues to collect damning evidence.
A number of non-government organizations, including the White Helmets, allege that a chemical weapons attack took place in Eastern Ghouta's town of Douma on April 7. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world.
Syria has been accused multiple times of using toxic weapons including sarin gas in the country's seven-year war, which has killed more than 350,000 people.