Israeli warplanes struck a radar system in Iran on Tuesday, Israel's Army Radio reported, hours after a ceasefire agreement intended to end a 12-day war came into effect.

Earlier, Israel said it had identified missiles from Iran hours into the ceasefire. Iran also reported that Israeli missiles had struck its territory about 90 minutes into the ceasefire.

While the Iranian missiles reportedly caused no injuries, they drew swift condemnation from Israel. "In light of the severe violation of the ceasefire ... we will respond with force," Israel's Chief of the General Staff Eyal Zamir said following a situational assessment.

Defense Minister Israel Katz said he had instructed the military to respond with "high-intensity strikes against regime targets in the heart of Tehran."

As Israel claimed attack on Iran's radar system, Iran's semi-official Fars news agency reported that an explosion sound was heard in Iran's northern city of Babolsar in Mazandaran province, and ambulances and rescuers are en route to the scene.

U.S. President Donald Trump, who announced the ceasefire, criticized both sides for breaching the truce and urged Israel to show restraint. "They both violated the ceasefire," Trump said as he departed the White House.

In a statement released later, Israeli Prime Minister Benjamin Netanyahu said that following his talk with Trump, "Israel has refrained from carrying out further attacks."