US President Donald Trump's special envoy to West Asia, Steve Witkoff, has privately warned top US Senate Republicans that Iran could unleash a mass-casualty response in the event of an Israeli attempt to bomb its nuclear facilities, official sources in the US say.

US President Trump has voiced optimism that diplomatic efforts on Iran’s nuclear activities would bear fruit, reiterating that he wants to "make a deal with Iran."

As indirect nuclear talks between Iran and the US resume in Rome, a review of their past diplomatic engagements offers a sobering reminder of why Iranian officials remain distrustful of the other side.

Iran’s Foreign Ministry spokesman Esmaeil Baghaei has warned that making fundamental mistakes could disrupt the negotiations between Tehran and Washington.

The remarks will be aimed at shaping public opinion and influencing the course of the talks, said the source.

At an emergency meeting with Netanyahu, Trump announced the resumption of talks with Iran for the first time since 2018, set to begin on Saturday.