The US-Iran talks began on Sunday in Switzerland, after last week's agreement, which includes a commitment to reach a final deal within 60 days.
The Israeli military accused Ahmed Wishah of being a "Hamas sniper operative", without providing evidence.
It comes a day after the US and Iran signed a deal to end their conflict, including fighting in Lebanon.
JD Vance has not travelled to Switzerland as the Israeli military said it was targeting Hezbollah and that four of its own soldiers had been killed.
Mona Khalil, who had refused to leave the beach she had spent years protecting, died after several days in hospital, an environmental group said.
At least 20 people have reportedly been killed by Israeli air strikes as the Israeli military said Hezbollah had fired at Israeli troops in southern Lebanon.
The agreement followed concerns that continued clashes would undermine the deal to end the war between the US and Iran.
Mojtaba Khamenei says he initially disagreed with the deal but allowed it go ahead after assurances from the Iranian president.
While the human cost is clear, the Iranian regime has not just survived the war, it has been empowered.
Trump has insisted the deal ensures that Iran will never buy, develop or produce a nuclear weapon. But text of the agreement falls short of that.
The fate of Iran's nuclear programme, a key reason cited by the US for starting the conflict, is still to be negotiated.
Speaking on Tuesday, Trump said Israel's PM Benjamin Netanyahu needed "to be more responsible with respect to Lebanon".
Experts say internet, media and government restrictions have all hampered casualty reporting across the region.
BBC analysts assess the claims by both Washington and Tehran to have won a victory with the deal to end their war.
The 14-paragraph memo includes an end to fighting, an agreement that Iran will never have a nuclear weapon, and a $300bn redevelopment package for Iran.
It's so hot the fuel can catch fire - the bikers tell the BBC they must live with the risk of injury and death.
Experts say that there are significant obstacles preventing traffic from returning to the levels seen before the conflict began – security, mines and tolls.
Travelling with a humanitarian convoy, BBC's Hugo Bachega has been given rare access to a part of Lebanon under Israeli occupation.
Lebanon says Israeli strikes kill 18 as Israel says four soldiers killed by Hezbollah
The 14-point Memorandum of Understanding was signed at a post-G7 dinner in France.
The BBC's Arabic Correspondent Carine Torbey explains how the deal is being viewed in one of the most hit areas of Lebanon.
The city's main liquified natural gas (LNG) processing site suffered a "technical accident" in the Ras Laffan industrial zone.
