US Secretary of State Antony Blinken was heading on Wednesday to talks in key mediator Qatar after Hamas gave a reply to a US-led proposal for a ceasefire in war-ravaged Gaza.

Blinken, on a four-country swing around the Middle East to push Hamas to accept the truce proposal, will meet the top leadership of Qatar, which has transmitted messages to the Palestinian militant group.

Hamas, responding to the plan laid out on May 31 by President Joe Biden, proposed amendments late Tuesday including a ceasefire timeline and the complete withdrawal of Israeli troops from Gaza, according to a source familiar with the talks.

The Biden plan calls for an Israeli withdrawal from "major population centres" and a ceasefire for six weeks, which would then be extended as negotiators reach a permanent deal.

The White House said Tuesday that the United States was "evaluating" the reply.

US officials had privately expected Hamas to insist on at least some changes rather than accepting the entire deal immediately, and want to see if there is enough common ground to hammer out differences with Israel.

Biden is eager to end a war that has taken a mounting toll on civilians and turned parts of his Democratic Party base against him months ahead of razor-close elections.

Blinken said in Israel on Tuesday that Prime Minister Benjamin Netanyahu has committed himself to the plan, although the Israeli government, which has far-right members, has not formally endorsed it.

Blinken on Tuesday pressed Hamas's elusive Gaza-based leader, Yahya Sinwar, to take the deal.

"Are they looking after one guy who may be for now safe -- buried, I don't know, 10 storeys underground somewhere in Gaza -- while the people that he purports to represent continue to suffer in a crossfire of his own making?" Blinken told reporters in Tel Aviv.

Israel says that Sinwar masterminded the October 7 attack that resulted in the deaths of 1,194 people, mostly civilians, according to an AFP tally based on Israeli official figures.

The Israeli army has responded with a devastating offensive in Gaza that has left at least 37,164 people dead, the majority of them civilians, according to the Hamas-ruled territory's health ministry.

Blinken will meet in Doha with both the emir, Sheikh Tamim bin Hamad Al-Thani, and Prime Minister Sheikh Mohammed bin Abdulrahman Al-Thani, who is also the wealthy kingdom's top diplomat, according to the State Department.

Later on Wednesday, Blinken will fly to Italy to join Biden at the summit of the Group of Seven major industrial democracies.