The move comes after the US revealed on Wednesday they have restocked the Israeli army with ammunition and plans to allow them further access to an emergency munitions store based in Israel.

The death toll in Gaza now stands at 1,364 according to health officials who say nearly 8,000 have been injured in the offensive that began on 7 July. Human rights organisations say 80 percent of those killed have been civilians, including some 315 children.

The announcement of 16,000 additional reservists in Israel means a total of 86,000 troops have now been called up since the Gaza assault began, according to an army spokesperson.

A senior military source told Ynet news that the reservists have been called up “to give the army the time needed to complete the mission. We’ll decide today where to place them and in which commands.”

Israel’s security cabinet, which met for five hours on Wednesday, unanimously decided to pursue attacks against Hamas “terrorist targets” including a network of tunnels, public radio said.

The additional soldiers could be used to supplement an expansion in the Gaza offensive, at a time when ceasefire efforts appear to be failing.

An Israeli official told Haaretz on Thursday that a truce is not close: “When we get a ceasefire proposal that answers our needs it will be examined.”

“The [military] will expand attacks against Hamas and the rest of the terror organisations,” the official said.

Nevertheless a two-member Israeli delegation travelled to Cairo late on Wednesday to discuss a possible ceasefire with Egyptian officials, who are also expected to host a Palestinian delegation later this week.

Meanwhile on Wednesday, the US Department of Defence said it had approved an Israeli request for ammunition, including some from a stockpile stored by the US military on the ground in Israel for emergency use.

An unnamed defence official told Reuters that Israel has already used the stockpile to refill supplies of grenades and mortar rounds in the past week.

The official said that although the ammunition came from the War Reserves Stock Allies-Israel, which is in place for emergency situations, the Israelis had not asked to use this store specifically.

“They didn’t ask for it from there but we gave it to them so we could rotate our stocks,” the official said.

A spokesperson for the Pentagon said the supplying of arms was part of their strong commitment to their relationship with Israel.

“The United States is committed to the security of Israel, and it is vital to US national interests to assist Israel to develop and maintain a strong and ready self-defence capability,” said Pentagon press secretary Rear Admiral Kirkby. “This defence sale is consistent with those objectives.”

State Department deputy spokesperson Marie Harf responded on CNN to concerns about whether rearming Israel could cause criticism of the US if they result in more civilian casualties in Gaza.

“We are going to stand by Israel and do a number of things to help it defend its security, whether it’s Iron Dome, which is of course a defensive system, or helping the Israelis with security funding,” she told CNN’s Wolf Blitzer. “We’re going to stand by them as they fight this threat but that doesn’t mean when we think they could do more we won’t say that.”

Amnesty International, however, has urged Washington to halt arms supplies to Israel.

“It is time for the US government to urgently suspend arms transfers to Israel and to push for a UN arms embargo on all parties to the conflict,” it said in a petition to US Secretary of State John Kerry.

News of the US allowing Israel to refill their munitions supplies came after a bloody day in Gaza, when more than 100 Palestinians were killed in military strikes.

17 people were killed in an Israeli strike on a crowded market in Shejaiya, which came during a four-hour ceasefire announced earlier by Israel. Early Thursday morning,15 people were killed in an attack on a UN school in Jabaliya, north of Gaza City, where several hundred displaced families had been seeking shelter.