Three members of the Iran-backed Lebanese group Hezbollah were killed in an Israeli drone strike in southwest Syria on Friday, according to two regional sources close to Damascus.

The strike also killed a Syrian who was accompanying them, one of the sources said.

The Israeli army declined to comment on the strike in Quneitra, also known as Baath City, near the frontier with the Israeli-occupied Golan Heights.

Israel has for years carried out attacks on what it has described as Iran-linked targets in Syria, where Tehran's influence has grown since it began supporting President Bashar al-Assad in a civil war that started in 2011.