Senior Gaza-based Hamas leader Mahmud Zahar pledged that the "principles and strategy of the Palestinian Islamic resistance will not change," during a visit to Tehran on Thursday, Iranian media reported.
Zahar, who is meeting Iranian officials, arrived in Tehran shortly after a fragile truce between Israel and Gaza-based militants was announced, ending four days of bloodshed.
During a meeting with the Hamas leader, Iranian Foreign Minister Ali Akbar Salehi voiced his country's support for the Palestinians.
He condemned Israeli air strikes during the recent outbreak of violence, calling them "savage attacks by the Zionist regime against the innocent Palestinian population," the official IRNA news agency reported.
"Support for the Palestinian population is part of our principles and religious beliefs, and we are certain that the Palestinian people will triumph," he said.
Zahar thanked Iran for its "limitless support."
On Wednesday, Zahar met the head of Iran's supreme national security council, Saeed Jalili, and the speaker of Iran's parliament, Ali Larijani, the IRNA said.
Jalili reportedly renewed Iran's unwavering support for the Palestinian cause and cautioned Zahar against "plots" seeking to divide the Palestinian resistance.
In recent months, divisions have opened between Hamas chief Khaled Meshaal, who lives in exile, and members of the group's Gaza leadership, including Zahar.
Meshaal has presented an increasingly moderate position, saying last May that he was ready to give negotiations with Israel "a chance," and offering tacit support for the establishment of a Palestinian state alongside Israel.
He has also publicly supported peaceful "popular resistance," and engaged in a reconciliation deal with rival Palestinian group Fatah, even backing an agreement to have Palestinian president and Fatah chief Mahmud Abbas serve as the head of a temporary consensus government.
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Those positions have put him at odds with much of the leadership in Gaza, which has warned that it expects to be consulted about key decisions, including reconciliation with Fatah and the principle of armed struggle.
"Jihad is our path, our life, our pride and we will not renounce it no matter the sacrifices," Zahar said in January.
Despite Meshaal's engagement with Fatah, the reconciliation efforts have largely stalled, and Palestine Liberation Organisation official Yasser Abed Rabbo warned on Thursday that he felt Hamas was uninterested in the process.
"I no longer believe that Hamas wants reconciliation," he told Voice of Palestine radio.
Zahar's visit follows one last week by Hamas's Gaza prime minister Ismail Haniya, who shared the podium with Iranian President Mahmoud Ahmadinejad on February 11 to commemorate the anniversary of Iran's 1979 Islamic Revolution.
On March 3, Zahar said Hamas was not taking sides in the conflict between the Syrian regime, Iran's main ally, and insurgents.
But Haniya, in a visit to Cairo last month, saluted "the heroic Syrian people, who are striving for freedom, democracy and reform," in a departure from the Islamists' refusal to criticise Damascus.
Meshaal last visited Tehran in October.
Israel and the United States consider Hamas to be an armed proxy of Iran and, on Wednesday, Israeli Prime Minister Benjamin Netanyahu branded Gaza an "advance post for Iran," explicitly accusing Tehran of arming, financing and training militants in the Palestinian enclave.
But despite the ties, Hamas has said publicly it would stay out of tensions between Israel and Iran over Tehran's nuclear activities.
Ahmed Yussef, a counsellor to the Hamas foreign ministry, told AFP earlier this month that "Iran does not need Hamas to respond to Israel in the event of an attack, because it has enormous military capabilities at its disposal, which allow it to act without us."