Hamas chief Yahya Sinwar said Monday the Palestinian group had the resources to sustain its fight against Israel, with support from Iran-backed regional allies, nearly a year into the Gaza war.
Sinwar, who last month replaced slain Hamas leader Ismail Haniyeh, said in a letter to the group's Yemeni allies that "we have prepared ourselves to fight a long war of attrition".
Deadly fighting raged on in the besieged Gaza Strip, where medics and rescuers said Monday that Israeli strikes -- which the military has not commented on -- killed at least two dozen people.
The latest strikes came as Israeli Defence Minister Yoav Gallant warned that prospects for a halt in fighting with Hezbollah militants in Lebanon were dimming, yet again raising fears of a wider regional conflagration.
Senior Hamas official Osama Hamdan told AFP at the weekend the group "has a high ability to continue" fighting despite losses, noting "the recruitment of new generations" to replace killed militants.
Gallant last week said Hamas, whose October 7 attack triggered the war, "no longer exists" as a military formation in Gaza.
Sinwar, in his letter to Yemen's Huthis, threatened that Iran-aligned groups in Gaza and elsewhere in the region including Lebanon and Iraq would "break the enemy's political will" after more than 11 months of war.
"Our combined efforts with you" and with groups in Lebanon and Iraq "will break this enemy and inflict defeat on it," Sinwar said.
Independent UN rights experts meanwhile warned that Israel risked international isolation over its actions in Gaza and called on Western countries to ensure accountability.
Spain, which recently joined several European countries in formally recognising the State of Palestine, is due to host Palestinian president Mahmud Abbas on Tuesday, an official in his office told AFP.
Abbas, who is based in the Israeli-occupied West Bank and holds little sway in Gaza, is set to meet Spanish King Felipe VI and Prime Minister Pedro Sanchez, before heading to New York for the UN General Assembly.
The October 7 attack on southern Israel that sparked the war resulted in the deaths of 1,205 people, mostly civilians, according to an AFP tally based on official Israeli figures.
Militants also seized 251 hostages, 97 of whom are still held in Gaza, including 33 the Israeli military says are dead.
Israel's retaliatory military offensive has killed at least 41,226 people in Gaza, according to the Hamas-run territory's health ministry, which does not provide a breakdown of civilian and militant deaths.
Tensions have surged along Israel's northern border with Lebanon, amid fears the violence could explode into an all-out war.
"The possibility for an agreement is running out as Hezbollah continues to tie itself to Hamas and refuses to end the conflict," Gallant told visiting US envoy Amos Hochstein, a defence ministry statement said.
Israeli media outlets said Prime Minister Benjamin Netanyahu was considering firing Gallant, one of several officials who have been at odds with the veteran leader on war policy. Netanyahu's office denied the reports.
Netanyahu told Hochstein later Monday he seeks a "fundamental change" in the security situation on Israel's northern border.
Lebanon's Iran-backed Hezbollah group has traded near-daily cross-border fire with Israeli forces since October in stated support of ally Hamas.
Hezbollah deputy chief Naim Qassem said Saturday his group has "no intention of going to war", but if Israel does "unleash" one "there will be large losses on both sides".
The violence has killed hundreds of mostly fighters in Lebanon, and dozens of civilians and soldiers on the Israeli side.
In central Gaza, survivors scoured debris Monday after a strike on the Nuseirat refugee camp.
Ten people were killed and 15 were wounded when an air strike hit the Al-Qassas family home in Nuseirat in the morning, said a medic at Al-Awda Hospital, where the bodies were taken.
"My house was hit while we were sleeping without any prior warning," said survivor Rashed al-Qassas.
Gaza's civil defence said six Palestinians were killed in a similar strike at night on a house belonging to the Bassal family in Gaza City's Zeitun neighbourhood.
Emergency services later reported six more deaths, with Al-Awda Hospital saying it received the bodies of three people killed in Israeli strikes on Nuseirat.
The Gaza war has drawn in Iran-backed Hamas allies across the Middle East, including Hezbollah in Lebanon and the Huthis, whose maritime attacks have disrupted global shipping through vital waterways off Yemen.
On Sunday the rebels claimed a rare missile attack on central Israel which caused no casualties, prompting Netanyahu to warn that they would pay "a heavy price for any attempt to harm us".
In a televised speech, the Huthis' leader said the rebels and their regional allies were "preparing to do even more".
"Our operations will continue as long as the aggression and siege on Gaza continue," Abdul Malik al-Huthi said.
