Hamas's chief negotiator Khalil al-Hayya said on Sunday that a targeted assassination by Israel on Saturday of one of the group's senior commanders threatens the "viability of the truce" in the Gaza Strip.
In a televised address, Hayya, who is also the exiled Gaza Hamas chief, confirmed the killing of the group's senior commander, Ra'ad Sa'ad, in an Israeli strike a day earlier.
It was the highest-profile assassination of a senior Hamas figure since a US-backed Gaza ceasefire deal came into effect in October.
"The continued Israeli violations of the ceasefire agreement...and latest assassinations that targeted Sa'ad and others threaten the viability of the agreement," he said in an address.
"We call on mediators, and especially the main guarantor, the US administration and President Donald Trump, to work on obliging Israel to respect the ceasefire and commit to it."
Deploying the International Stabilization Force
Hamas sources have described Sa'ad as the second-in-command of the group's armed wing, after Izz al-Din al-Haddad. Israel says Sa'ad was one of the key architects of the October 7 attack on Israel that triggered the war.
Hayya also spoke about the proposed UN-authorized International Stabilization Force (ISF).
"The role of the international forces should be limited to maintaining the ceasefire and separating the two sides along Gaza borders...without any role inside the strip or intervention in its domestic affairs," he said.
Deployment of the force is a key part of the next phase of Trump's Gaza peace plan. Under the first phase, a fragile ceasefire in the two-year-old war began on October 10 with Hamas releasing hostages and Israel freeing detained Palestinians.
The US Central Command will host a conference in Doha on December 16 with partner nations to plan the International Stabilization Force for Gaza, US officials told Reuters.