Air strike sirens in Israel, as rockets crash into Israel's 'iron dome' missile defense system.
Hamas militants fired ten long-range missiles at Tel Aviv -- the country's most populated city and business hub.
The missile launch caused no casualties or damage, but it's the most ambitious one so far directed at Israel --- which is in its fifth day of a military operation targeting Gaza, that has already killed at least 125 people.
The U.N. expressed concern over the rise in tensions, calling for a ceasefire on both sides.
But Israeli defense officials warn that their troops may enter Gaza in the days ahead, with some 20,000 reservists prepared for a possible invasion.
