The upsurge has highlighted, again, the total disparity of force between the two sides. Israeli aircraft and naval units can operate against targets in the Gaza Strip more or less at will. If there were to be a major ground incursion by Israel — something that both sides would probably want to avoid — the military balance again would be overwhelmingly in Israel’s favour.

Equally though, the fighting has highlighted the pervasive risk posed by the Palestinian rocket arsenal to Israeli citizens living in the southern part of the country.

Palestinian rockets may not be especially sophisticated or accurate.

Nonetheless, they remain a serious threat, as the direct hit on an apartment building in Kiryat Malachi on Thursday morning, which left three dead, demonstrated.

Israeli towns or cities in a broad arc south of Tel Aviv are all potentially within range of these rockets. Hundreds of thousands of Israelis live in their shadow..

The Palestinian rocket arsenal is large and gradually improving over time. Many of the shorter-range systems, like the Qassam — a generic name for a whole family of weapons — are built in factories and workshops in the Gaza Strip itself. These have ranges up to a dozen or so km. Grad missiles, many thought to be supplied by Iran, have a 20 km reach — though some upgraded versions may have a considerably longer range.

A Chinese-designed rocket, the WS-1E, has also been used with a range of around 40 km. The most potent weapons in are the Fajr-5 rockets. These have a potential range of up to 75 km, threatening the fringes of Tel Aviv — Israel’s largest city. Storage sites for these weapons have been among the specific targets sought out by Israeli aircraft.

Israeli military spokesmen claim to have been remarkably successful in destroying them, though there are reports that at least one Fajr-5 has been fired during the current round of fighting.

Israel’s response has been both defensive and offensive. Its relatively new anti-missile system — Iron Dome — is heavily engaged. It has been operational since 2011. Each of the four batteries can defend an area the size of a medium-size town. Powerful radars track missiles; their likely landing point is estimated and the battery then fires interceptor missiles at those heading for populated areas. — © BBC News/Distributed by the New York Times Syndicate