Israel launched fresh air strikes on Gaza on Thursday as tensions escalated with rockets reportedly being launched from the area into Tel Aviv for the first time in two decades.
The BBC reported fresh strikes hitting Gaza with the Middle East Bureau Chief tweeting he could hear "kids crying in flats next door from fear."
Militant group Islamic Jihad claimed responsibility for a rocket attack fired at Israel's biggest city Tel Aviv.
According to the Israeli Defence Force the two missiles did not hit the area, instead reports indicate they landed in the sea.
But following the attack Israeli Defence Minister Ehud Barak spoke out against the "escalation," warning it would "exact a price that the other side will have to pay."
According to Reuters Islamic Jihad said in a statement they had fired a Fajr 5 rocket, saying they had "widened the range of the battle to reach Tel Aviv and what is coming will be greater."
Hamas' prime minister, Ismail Haniyeh, said those in Gaza would "fend off the aggression."
"We here in Gaza will remain steadfast and unshaken," he said.
30,000 Israeli army reservists are on stand by to be called up in preparation for a ground assault.
According to Israel 274 missiles have been fired into Israel since yesterday.
It comes after Israel killed the leader of the Hamas military wing in a surgical missile strike in Gaza that could result in a fresh war in the region.
Ahmed Jabari, 46, the head of the Islamist group's military arm, the Izz ad-Din al-Qassam, died as he travelled by car with another senior Hamas leader in the Palestinian city.
David Cameron spoke to the Israeli prime minister Benjamin Netanyahu on Thursday evening and called on Israel to do all it could to avoid civilian casualties, a Downing Street spokesperson said.
"He called on Mr Netanyahu to do all he could to avoid civilian casualties and emphasised that both sides needed to avoid a spiral of violence that would be in no-one's interest, particularly at a time of instability in the region," they said.
Fifteen palestinians have died in the last two days since the Israeli attack. Earlier on Thursday three Israelis were killed by rockets coming from Gaza.