Israel has carried out a series of air strikes overnight on the Gaza Strip.
Hamas claims six of its members were killed in a single attack near Rafah. Three others died in separate strikes.
Israel said the attacks were ordered after rockets and mortars, launched from Gaza, landed in the south of the country.
Tensions in the region are at breaking point after the murder of Palestinian teenager Mohammed Abu Khdair.
His death followed the kidnap and killing of three young Israelis in the West Bank.
Israel blames Hamas for the slayings and has arrested hundreds of Palestinians following the abduction of the young men.
The three were found buried in a shallow grave last week.
Freddy Eytan, an Israeli political analyst, believes Israeli Prime Minister Benjamin Netanyahu will remain calm, despite the violence: “Netanyahu is not a warmonger, he has not ordered extensive operations like [former Prime Minister Ehud] Olmert did in Lebanon and Gaza. He is not hesitating, he is careful, prudent. I think he will manage the situation until Gaza goes quiet again.”
On Sunday Israel made six arrests in connection with the murder of Mohammed Abu Khdair.
The teenager was abducted last Wednesday and reportedly burnt to death.
Prime Minister Netanyahu said: “We will not allow extremists, it doesn’t matter what side, to inflame the region and cause bloodshed.”
The six in detention are described as young males, including minors, from Jerusalem.