UN humanitarian chief says bombardments on Gaza ‘getting worse’; Gaza health ministry releases 212-page document of names of 7,000 it says have been killed

• Israel and Hamas at war: what we know on day 20

As the death toll mounts in Gaza, Palestinians are burying the unidentified dead in mass graves, with a number instead of a name, residents say. Some families are using bracelets in the hope of finding their loved ones should they be killed.

Israeli retaliatory strikes have killed over 6,500 people, the health ministry in the Hamas-run strip said on Wednesday.

Biden said on Wednesday he had “no confidence in the number that the Palestinians are using” for the death toll, but he did not say why he was skeptical. The United Nations relies on the Gaza ministry for death toll figures.

In the US, the Council on American-Islamic Relations (CAIR) said it was “deeply disturbed” by Biden’s comments on the Gaza figures, and called on the president to apologise.

Israeli tanks and troops are massed on the border with Gaza awaiting orders, Reuters reports. Israel has called up 360,000 reservists.

International pressure is growing to delay any invasion of Gaza, not least because of hostages. More than half the estimated 220 hostages held by Hamas have foreign passports from 25 different countries, the Israeli government said. Many were believed to have had dual Israeli nationality.

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.