Air raid sirens sounded in Jerusalem on Friday and Israeli Army Radio said the alert was intended for Israeli towns near the holy city.
The siren lasted for less than a minute. The radio said its reporter in Jerusalem heard an explosion. No blast was heard in the Reuters bureau in the south of the city.
In Gaza, Hamas's military wing said it had fired a long-range rocket at Jerusalem, about 70 km (40) miles from the Palestinian enclave.
Israeli police said they had no immediate information on whether a rocket had hit the city.
© Thomson Reuters 2012