This blog has now closed. You can follow the Guardian’s continuing live coverage of the Israel-Hamas conflict here.

The US has advised Israel to hold off on a ground assault in the Hamas-controlled Gaza Strip and is keeping Qatar – a broker with the Palestinian militants – apprised of those talks, sources have told Reuters.

Echoing reports in other media including the New York Times, the newswire reported:

After Hamas attacked Israel on 7 October and killed some 1,400 people, the United States stood by its ally and stressed that Israel has the right to defend itself. It has also publicly stressed that Israel will decide its own timetable for retaliation.

But the White House, Pentagon and State Department have now stepped up private appeals for caution in conversations with the Israelis, two sources familiar with discussions said, as Israel’s blockade of Gaza worsens a humanitarian crisis and the death toll from its bombardment of the enclave passes 5,000.

More than 350,000 reservists have joined the forces massed in southern Israel and awaiting orders

• Israel and Hamas at war – live updates

The double line of Israeli tanks stretched to the horizon. About 100 were visible, low-slung hulks quickly taking on the colour of the pervasive desert dust. This was just a small part of Israel’s coiled military might ranged along the borders of Gaza, waiting for the order to move. Israel has about 2,200 tanks, a massive force, 10 times the British army’s tank fleet, and many of them are here, fuelled up and pointing west.

About 20 miles (30km) to the north, near the border town of Sderot, huge self-propelled guns have been dug into the earth, angled towards Beit Hanoun and Gaza City, which lie just over the crest of a hill. Lorries and tankers carrying fuel and water run in convoys along the Israeli roads that run north to south, parallel to the Gaza border, and reservists fill the streets, cafes and petrol stations of the border towns that absorbed the brunt of the 7 October Hamas attack that ignited the current war.

Red Cross confirms release of two more Hamas hostages; Biden official says ‘we should have those hostages released and then we can talk’

• Hamas and Israel at war: what we know on day 17

The leaders of the US, UK, France, Canada, Germany and Italy have called on Israel to adhere to international law and protect civilians, while also reiterating Israel’s right to defend itself against terrorism.

In a statement put out after a phone call, the leaders’ offices said:

The leaders reiterated their support for Israel and its right to defend itself against terrorism and called for adherence to international humanitarian law, including the protection of civilians.

They welcomed the release of two hostages and called for the immediate release of all remaining hostages. They committed to close coordination to support their nationals in the region, in particular those wishing to leave Gaza.

The leaders committed to continue close diplomatic coordination, including with key partners in the region, to prevent the conflict from spreading, preserve stability in the Middle East, and work toward a political solution and durable peace.

At least 400 Palestinians killed in last 24 hours, including 70 in refugee camp and near hospitals

• Israel and Hamas at war – live updates

The blockaded Gaza Strip has been hit by one of the deadliest nights of Israeli bombing so far in the war against the Palestinian militant group Hamas, as two more hostages were freed amid reports that talks to secure the release of dozens of others were under way.

At least 400 Palestinians were killed in Gaza in the last 24 hours, according to the Hamas-run health ministry, and 70 were killed overnight on Sunday in bombardments of the densely populated Jabalia refugee camp and streets close to two hospitals in Gaza City.

Families given glimmer of hope by release of two US citizens, but fear time is running out before ground invasion

• Israel-Hamas war: latest updates

Pressure has intensified on Israel to negotiate the release of more than 200 people held by Palestinian militants in Gaza, with desperate families begging officials to help free their loved ones before an anticipated ground invasion.

An Israeli military spokesperson announced on Sunday that more than 212 people were held in Gaza, as officials worked to identify and locate those missing after a deadly incursion by Hamas on 7 October.