The sons of Supreme Leader Ali Khamenei visited the Hamas office in Tehran on Friday, extending condolences for the death of Yahya Sinwar, according to the Supreme Leader's official website.

Mojtaba Khamenei is widely seen as a frontrunner to succeed his father as Supreme Leader and the move may signal a desire to continue backing armed allies abroad as Hamas pledged to carry on its fight with mutual arch-foe Israel.

“In this meeting, they underscored Ayatollah Khamenei's recent directive to extend support to the people of Palestine and Lebanon, detailing the Iranian nation’s collective contributions,” the website read.

“They highlighted the national campaign 'Iran in Solidarity' as a prominent example of these efforts, symbolizing unity with the fighters and resilient communities of Palestine and Lebanon,” it added.

Khaled Qaddoumi, Hamas’s representative in Tehran, said following the meeting that the death of its leader would not undercut the group's strength.

"(Sinwar) devised a mechanism for leading the Resistance so that in his absence things would not come to a standstill," he said. "Today, no gap in the leadership of the resistance is felt."

US Secretary of State Anthony Blinken was in the Qatari capital Doha to restart talks over a Gaza ceasefire on Friday, but Qaddoumi sounded a defiant note.

“The Americans believe that now is a good opportunity to eradicate the resistance, but, God willing, this will not happen. The era of America is over,” Qaddoumi added.

As Israeli threatens to strike Iran, the hardline core of the establishment shows little sign of backing down in its support for Hamas and Hezbollah. However, efforts by Iranian authorities to raise public donations for Hezbollah have stirred anger among citizens who have been facing five years of 40% annual inflation.

While levels of support have varied over time, US officials estimated in 2018 that Iran provides approximately $700 million annually to Hezbollah.