Israeli prime minister set to authorise call-up of more reserve soldiers, as death toll from Israel's bombing passes 200 in Gaza

The Israeli prime minister, Binyamin Netanyahu, has warned that Hamas "shut the door to a diplomatic solution" to the crisis in Gaza as his government was set to authorise the call-up of another 8,000 reserve soldiers in the escalating conflict.

Israel, however, did agree to a UN request to halt its bombardment for five hours on humanitarian grounds after its naval strikes killed four children on a beach. Hamas reportedly also agreed.

After Hamas formally rejected the ceasefire proposal tabled by Egypt on Monday, Netanyahu said the Islamic organisation bore "sole responsibility for the continuation of the violence". He accused it of war crimes, in targeting Israeli citizens and using Palestinian civilians as human shields.

His comments on Wednesday came after another day of bloodshed in Gaza, where the death toll passed 200. An Israeli civilian was also killed on Tuesday. Israel said more than 1,200 rockets had been launched from Gaza since the start of the nine-day conflict and its forces had carried out more than 1,825 air strikes.

The extra reservists will join thousands of others who are on standby in the event of a ground invasion by the Israeli military into Gaza. Although Israel has warned that the deployment of troops and tanks is a real possibility, Netanyahu will have to calculate the potential gains against the increased risk of soldiers being killed and Israel being drawn into a long term reoccupation of Gaza.

Hamas's rejection came as reports emerged of a "secret" weekend telephone call between Netanyahu and the Egyptian president, Abdel Fattah al-Sisi, to discuss a possible ceasefire. According to the Israeli newspaper Haaretz, Tony Blair brokered the contact, which resulted in the Egyptian proposal to an immediate "de-escalation", followed by a ceasefire and then talks on a long-term agreement. Blair was thought to be in continued contact with both leaders.

Palestinian leaders in Gaza are enraged at their exclusion and deeply suspicious of Blair's involvement. They believe the Middle East envoy has a record of acting in Israel's interests, and they resent his support for Sisi, who has outlawed Hamas's allies Muslim Brotherhood and hardened attitudes towards Gaza.

Israel's six-hour respite in air strikes on Tuesday in response to the ceasefire call as Hamas continued to fire rockets has allowed it to claim some moral high ground, despite the continuing deaths of civilians, including children, and the destruction of homes and infrastructure in Gaza.

On Wednesday, US president Barack Obama backed Egypt's efforts to broker a ceasefire, offering Washington's full diplomatic support. He said that while he and the world were "heartbroken" by the deaths of civilians in the Gaza Strip, Israel had the "right to defend itself from rocket attacks that terrorise" its population.

"We're going to continue to encourage diplomatic efforts to restore the ceasefire, and we support Egypt's continued efforts to bring this about," he said.

"Over the next 24 hours, we'll continue to stay in close contact with our friends and parties in the region, and w e will use all of our diplomatic resources and relationships to support efforts of closing a deal on a ceasefire."

Netanyahu has been criticised by several of his most senior ministers for his handling of the crisis, forcing him to sack deputy defence minister, Danny Danon, a member of Netanyahu's Likud party, on Tuesday evening.

Danon had told the media that Hamas had humiliated Israel by setting conditions for peace, after Netanyahu said he was willing to accept the Egyptian-brokered ceasefire.

"At a time when … Israel and the IDF [Israeli Defence Forces] are in the midst of a military campaign ... it cannot be that the deputy defence minister will sharply attack the leadership of the country regarding the campaign," Netanyahu said on Tuesday.

"These sharp remarks on the deputy defence minister's part are irresponsible, especially given his position. They also serve the Hamas terrorist organisation as a tool to attack the government with."

The divisions within the Israeli cabinet were mocked by Hamas, with spokesman Fauzi Barhoum calling the sacking of Danon a "victory for the resistance".

Avigdor Lieberman, Israel's hawkish foreign minister, split his Yisrael Beiteinu party from Likud – dismantling a crucial alliance with Netanyahu – having accused the prime minister of hesitation over Gaza.

Lieberman criticised the government for accepting the Egyptian-brokered ceasefire and called for an IDF ground assault and occupation of the Gaza Strip, arguing that a ceasefire would allow Hamas and other Palestinian militant groups to replenish their stock of weapons.

"All this hesitation works against us. We must go all the way, there is no alternative. We have to end this conflict with the IDF in control of all of Gaza … There is no other way to tackle the Hamas and Islamic Jihad terror that rules Gaza," Lieberman said at a press conference on Tuesday night.

Israeli media reported that another senior figure on the Israeli right, Naftali Bennett, who leads the Jewish Home party, also voted against a ceasefire.

Netanyahu is susceptible to pressure from rightwing parties as his shaky coalition government depends on them. Meanwhile, pro-peace activists in Israel are struggling to make their voices heard against popular support for the Israeli military campaign.

A peace protest on Saturday night in Tel Aviv was eventually called off, with only a handful of protesters turning out. Peace campaigners in Tel Aviv and Jerusalem have been attacked by gangs of rightwing counter-protesters.

Alon Lee-Green, 26, a Tel Aviv bookshop owner and peace activist, said he had attended protests in Tel Aviv, Haifa and Jerusalem in recent days, but numbers were far lower than during the 2012 war in Gaza.

"The problem is that, on the one hand, we are not allowed by the army to gather more than 500 people together when there are missiles and sirens, but on the other we also feel a bit lost over [whether] we call a big crowd of people together while there is a danger of an alarm," he said.

A 67-year-old ex-soldier, who declined to give his name, aid Israel was ready to make peace but did not have a partner in the Palestinians. Until it did, he said the war was likely to continue.

"The problem with these groups – Hamas, Hezbollah – is that they say they want peace but what they really want is to push us into the sea," he said. "You give them Gaza and tomorrow they will be asking for Jaffa."