Tel Aviv, Palestine (BBN)-The UN Security Council has called for a ceasefire between Israel and the Palestinians in the Gaza Strip.
Israeli air strikes hit the territory's security HQ and police stations early on Sunday, in what a BBC correspondent described as the heaviest bombardment since operations began on 8 July.
An earlier air strike is said to have killed 17 members of the same family, reports BBC.
Meanwhile, Israel says it has sent ground forces into Gaza in a raid on a rocket-launching site.
Four soldiers were "lightly injured" in a successful raid on the site, the Israel Defence Forces said on its Twitter feed.
Israel says it was hit about 90 rockets fired from Gaza on Saturday and also reported intercepting three rockets fired at Tel Aviv from the coastal territory by Hamas Islamist militants.
A total of at least 159 Palestinians have been killed and more than 1,000 injured since Israel began its operation six days ago, Palestinian sources say.
Wars between Hamas and Israel tend to finish with some sort of ceasefire.
Factors influencing the timing of a deal include the amount of blood spilt, and the level of international pressure on both sides to make a deal.
It looks as if that point has not yet been reached. Ceasefires involve a certain loss of face, as leaders glide away from some of the rhetoric they threw around when the guns started to fire.
Neither side is ready for that yet. This conflict may have to get worse before the pressure for a ceasefire becomes unanswerable.
All 15 members the UN Security Council approved a statement calling for calm and peace talks.
It is the first time since Israel's offensive began that they have issued a statement, with members previously divided on their response.
The BBC's Nick Bryant reports from the UN that the problem has been finding a form of words that Arab nations, represented on the Security Council by Jordan, find meaningful – but which the US, Israel's close ally, could also agree with.
Israel has vowed to press on with its campaign until rocket attacks stop. Five Israelis have been injured this week by rocket and missile attacks, two of them seriously, but no Israelis have died.
Israel says it is targeting militants and militant facilities, including the homes of senior operatives. "Dozens of terrorists" are among those who have been killed, it says.
However, the UN has estimated that 77% of the people killed in Gaza have been civilians.
The Security Council members expressed serious concern regarding the crisis related to Gaza and the protection and welfare of civilians on both sides.
The Security Council members called for de-escalation of the situation, restoration of calm, and reinstitution of the November 2012 ceasefire.
The Security Council members further called for respect for international humanitarian law, including the protection of civilians.
The Security Council members also expressed their support for the resumption of direct negotiations between the Israelis and Palestinians with the aim of achieving a comprehensive peace agreement based on the two-state solution.
The 17 members of the same family were killed when four missiles hit a three-storey building in Gaza City on Saturday evening, a Gaza health official said. About 30 others were injured.
The house belonged to Gaza's police chief, Tayseer Al-Batsh, who was wounded.
Hamas spokesman Sami Abu Zuhri described the raid as "a heinous crime", adding: "Israel will pay a heavy price for its aggression against the Palestinian people."
Israel warned residents in the north of the Gaza Strip on Saturday evening to leave their homes "for their own safety".
However, Gaza's interior ministry has criticised the warning as "psychological warfare" and urged residents to stay put, AP news agency reports.
'NO KNOCKOUT'
Israel is deploying an eighth "Iron Dome" anti-missile battery as it mobilises thousands of army reservists for a possible major land operation inside Gaza.
A senior military official said Israel estimated Hamas still had thousands of rockets in its arsenal and it would take Israel more time to eliminate the threat to its civilians.
"There is no knockout," he told the Associated Press news agency, speaking on condition of anonymity. "It is more complicated."
A spokesman for Hamas said it would not "beg for calm" and would "continue to defend" its people.
"Once we are offered a genuine, coherent and serious proposal, we will look into it," he added, quoted by Reuters news agency.
UK Foreign Secretary William Hague has said he will discuss with his US, French and German counterparts the need for a ceasefire when they meet on Sunday in Vienna.
Israel and militants in Gaza fought an eight-day war in November 2012, which ended with a truce.
Rocket fire and air strikes increased after the abduction and killing of three Israeli teenagers in June, which Israel blamed on Hamas and which led to a crackdown on the group in the West Bank. Hamas denied being behind the killings.
Tensions rose further after the suspected revenge killing of a Palestinian teenager in Jerusalem on 2 July. Six Jewish suspects were arrested over the youth's abduction and murder.
BBN/AS-13July14-11:00am (BST)
