Iran fired about 200 ballistic missiles at Israel on Tuesday evening, an attack that marks a sharp escalation in a long-simmering conflict that could tip the region into a full-blown war.

A spokesman for the Israeli military, Rear Adm. Daniel Hagari, said that a handful of missiles had landed in central and southern Israel, but that most of them had been intercepted.

Iran last attacked Israel in April, in retaliation for the killings of its senior generals in Damascus, Syria. Israel, with help from the United States, Jordan and others, intercepted almost all of the more than 300 drones, ballistic missiles and cruise missiles fired at its territory at that time.

To intercept aerial attacks, Israel uses a multilayered air defense system. Two of the main weapons are the Iron Dome and the Arrow 3. In the April attacks, the Iron Dome and the Arrow 3 shot down most of the missiles and drones, while others were shot down by the United States and other allies.

Here’s a look at the two Israeli systems:

Iron Dome

Israel’s Iron Dome defense system can intercept many types of rockets and missiles that fly in high arcs and so can be difficult to stop. The Iron Dome became operational in 2011 and got its first big test over eight days in November 2014, when Gaza militants fired some 1,500 rockets at Israel. Israeli officials claimed a success rate of up to 90 percent during that conflict, though outside experts were skeptical.

The system’s interceptors — just 6 inches wide and 10 feet long — rely on miniature sensors and computerized guidance to zero in on short-range rockets. Israel’s larger interceptors — like the Arrow system — can fly longer distances to go after bigger threats.