A Palestinian rocket has hit the outskirts of Jerusalem, landing harmlessly in an open area in one of the longest strikes fired from the Gaza Strip in nearly a week of fighting.

The attack, the second aimed at the city since the Israeli offensive began a week ago, set off air raid sirens. A distant explosion could be heard in the city centre. Residents ran for cover as buses and trains stopped to let passengers off.

Police said the rocket landed in Gush Etzion, a collection of Jewish West Bank settlements south-east of the city. Last Friday's attempt to hit Jerusalem landed in the same area. No one was wounded in either attack.

Jerusalem, nearly 50 miles from Gaza, is the most distant city the militants have targeted, signalling an increasing sophistication in their arsenal.

The attacks aimed at Jerusalem and the Tel Aviv area have dramatically showcased the militants' new capabilities, including a locally made M-75 rocket that appears to have taken Israeli defence officials by surprise.

Both areas had remained outside their reach in past rounds of fighting, and their use dramatically escalated the hostilities. For more than a decade, the militants' range had been limited to steadily broadening sections of southern Israel.

The attack on Jerusalem was especially audacious, both for its symbolism and its distance from Gaza. Jerusalem had previously been considered beyond the range of Gaza rockets - and an unlikely target because it is home to the Al-Aqsa Mosque compound, Islam's third-holiest shrine.