Life for Palestinians in Gaza has deteriorated to unprecedented levels, agency says.
Security officials say it is not clear who was behind the attack.
Islam Shahwan, a police spokesman, said the second bomb exploded near the home of Marwan Abu Ras, the Hamas official responsible for publishing religious edicts, in Gaza.
No one was reportedly hurt.
Shahwan said two members of the Fatah movement of Mahmud Abbas, the Palestinian president, had been arrested in connection with the second blast, and that one of them had placed the bomb.