By Tala Ramadan, Jana Choukeir and Nidal al-Mughrabi

DUBAI/CAIRO (Reuters) -Hamas’ top leader Ismail Haniyeh was buried in Qatar on Friday following his assassination in the Iranian capital Tehran, and his possible succcessor told mourners his death would only make the Palestinian militant group more determined in its struggle against Israel.

Haniyeh’s death was one in a series of killings of senior Hamas figures as the war in Gaza between Hamas and Israel nears its 11th month and concern grows that the conflict is spreading across the Middle East.

Hamas and Iran have both accused Israel of carrying out the assassination and have pledged to retaliate against their foe. Israel has not claimed responsibility for the death nor denied it.

Haniyeh was laid to rest in a cemetery in the city of Lusail after a funeral ceremony at the Iman Mohamed Ibn Abd Al-Wahhab Mosque in Qatar’s capital Doha.

His coffin, draped in the Palestinian flag, was carried in a procession past hundreds of people along with the casket of his bodyguard, who was killed in the same attack in Tehran on Wednesday.

Mourners at the ceremony included Khaled Meshaal, who is tipped to be the new Hamas leader. Other senior Hamas officials and Qatar’s Emir Sheikh Tamim bin Hamad al-Thani also attended.

Speaking at the mosque, where Haniyeh’s body was laid for prayers, Meshaal said his death would only make the group more determined to continue its fight for a free Palestine. There would be no concessions over its principles and no recognition of Israel, he said.

“Palestine will remain from the river to the sea…and the Zionists (Israel) have no place on the land of Palestine, regardless of how many they kill of us,” Meshaal said in a video released by Hamas.

Haniyeh’s death was a big loss to the movement but it would not alter their course, he said.

“Our enemies don’t learn the lesson, they have been killing our leaders for over 100 years, what happened? When a leader ascends (to heaven) another leader comes,” he said.

Senior Hamas official Sami Abu Zuhri told Reuters by phone: “Our message to the occupation (Israel) today is that you are sinking deep in the mud and your end is getting closer than ever. The blood of Haniyeh will change all equations.”

Haniyeh was killed by a missile that hit him directly in a state guesthouse in Tehran where he was staying, senior Hamas official Khalil Al-Hayya said in Tehran.

The strike was one of several recent hits that have killed senior figures in Hamas or the Lebanese movement Hezbollah in a conflict that is now stretching from Gaza to the Red Sea and the Lebanon-Israel border and beyond.

In the United States, U.S. President Joe Biden said Haniyeh’s killingwas not helpful to international efforts to secure a ceasefire in the war in Gaza.

“It doesn’t help,” Biden told reporters on Thursday, when asked if the action ruined the chances of a truce.

Qatar has been leading the peace effort along with Egypt and the United States, Israel’s main ally.

WIDOW MOURNS

Haniyeh was the face of Hamas’ international diplomacy as an Israeli offensive destroyed Gaza.

He was seen by many diplomats as a pragmatist compared to the more hardline members of the Iran-backed group inside Gaza, although some Israeli commentators have said he was considered by some on the Israeli side as an obstacle to a deal.

Three of his sons were killed in an Israeli airstrike in the besieged enclave in April along with four of his grandchildren, Hamas said.

For Palestinian supporters, the Hamas leadership are fighters for liberation from Israeli occupation, keeping their cause alive when international diplomacy has failed them.

To Israelis and Western states, the Iran-backed Hamas, which has directed suicide bombings in Israel and fought frequent wars against it, is a terrorist group bent on Israel’s destruction.

Appointed to the Hamas top job in 2017, Haniyeh moved between Turkey and Doha, escaping the travel curbs of the blockaded Gaza Strip.

In May, the International Criminal Court prosecutor’s office requested arrest warrants for three Hamas leaders, including Haniyeh, as well as Israeli Prime Minister Benjamin Netanyahu for alleged war crimes. Israel and Palestinian leaders have dismissed the allegations.

Israel has announced that an air strike it mounted last month assassinated Hamas military leader Mohammed Deif in Gaza. Hamas has not confirmed or denied the death of Deif.

Hezbollah said that its senior military commander Fuad Shukr had been killed in an Israeli strike on a building in Beirut on Tuesday and it vowed a “definite” response to his killing.

(Reporting by Imad Creidi in Doha, Tala Ramadan and Jana Choukeir in Dubai and Nidal al-Mughrabi in Cairo; Writing by Michael Georgy; Editing by Angus MacSwan)