People across Iran got an anonymous text message from an unknown number stating, 'The US President is a man of action. Wait and see', reported Iranian state media on Monday.
The text, written in Persian, comes amid various rhetorical attacks on the regime in Tehran by the US government.
The Embassy of India in Tehran has advised Indian nationals currently in Iran to leave the country in view of the evolving security situation.
"In continuation of the advisory issued by the Government of India on 5 January 2026, and in view of the evolving situation in Iran, Indian nationals who are currently in Iran -- students, pilgrims, business persons and tourists -- are advised to leave Iran by available means of transport, including commercial flights," the fresh advisory issued on Monday read.
US President Donald Trump had earlier said he is considering a 'limited military strike' on Iran. Iran warned on Monday that it would respond 'ferociously' to any 'act of aggression'.
The United States has built up forces in the Middle East to pile pressure on Iran to make a deal at negotiations due to restart on Thursday, with Trump weighing a limited strike if no agreement is reached.
Iran's foreign ministry reiterated that any strike, even a limited, "would be regarded as an act of aggression. Period".
"And any state would react to an act of aggression as part of its inherent right of self-defence ferociously so that's what we would do," ministry spokesman Esmaeil Baqaei said at a briefing in Tehran attended by an AFP journalist.
The two countries concluded a second round of indirect talks in Switzerland on Tuesday under Omani mediation.
Further talks, confirmed by Iran and Oman but not by the United States, are scheduled for Thursday.
The European Union, which has been sidelined in mediation on Iran, called for a diplomatic solution ahead of the talks.
"We don't need another war in this region. We already have a lot," EU foreign policy chief Kaja Kallas said ahead of a meeting of EU foreign ministers.
"It is true that Iran is at its weakest point that they have been. We should be really using this time to find a diplomatic solution."
Iran's clerical authorities have faced recent steep challenges, including a wave of mass protests that peaked in January, last year's 12-day war with Israel, and the weakening of Iran's regional proxies.
(With inputs from AFP)