Israel has vowed to retaliate for Iran's recent missile attack, prompting fears of an escalating conflict and renewing focus on the military capacities of each country.

Explosions were heard over Tel Aviv and Jerusalem but there were no reports of Israeli deaths. A U.S. official said the attack was "effectively defeated."

The direct military strike on Tuesday came after senior military commanders of the Revolutionary Guards Corps convinced the country’s supreme leader, Ayatollah Ali Khamenei, that it was the only course of action if Iran wanted to appear strong, according to three Iranian officials.