The external affairs ministry on Monday advised all nationals against non-essential travel to Iran and urged Indians living in the Persian Gulf country to exercise caution as protests against a failing economy intensified and spread to 26 of its 31 provinces.

“In view of recent developments, Indian nationals are advised to avoid non-essential travel to the Islamic Republic of Iran until further notice. Indian citizens and PIOs currently in Iran should exercise due caution, avoid areas of protests or demonstrations, and closely monitor news as well as the website and social media handles of the embassy of India in Tehran.

“Indian nationals living in Iran on resident visas are advised to register with the Indian embassy, if not already done so,” the ministry said in its travel advisory.

The advisory was issued in the face of escalating protests and a fresh warning from US President Donald Trump of intervention if more protesters died at the hands of the Iranian regime.

A BBC report quoted human rights activists as saying protests had taken place in 26 of the country’s 31 provinces since last week, and that at least 19 protesters and one member of the security forces had been killed.

The protests were triggered by a sharp fall in the value of the Iranian currency, the rial, against the US dollar.

Last week, Trump warned Iran against a crackdown on protesters. “We are locked and loaded and ready to go,” he had said in a post on social media without elaborating.

Trump said on Sunday night: “We’re watching it very closely. If they start killing people like they have in the past, I think they’re going to get hit very hard by the United States.”

In June last year, the US carried out air strikes on Iran’s nuclear sites.