A Bangladeshi court on Sunday granted interim bail to a senior woman investigative journalist who was arrested on charges of violating a colonial-era official secrecy law that triggered widespread protests, including by the UN.

Rozina Islam, a senior reporter of Bangla daily Prothom Alo, the largest daily newspaper based on circulation, was on Monday last detained for over five hours by Health Ministry officials for allegedly clicking a picture of a document with her cell phone without permission. She was later arrested by the police.

The court of Metropolitan Magistrate Mohammad Baki Billah granted her bail on a bond of Tk 5,000 (approximately USD 59) with two guarantors -- one of whom must be a lawyer, and the other a legal guardian. She was also granted bail on condition of submitting her passport, The Daily Star newspaper reported.

While pronouncing the bail order, the magistrate said, "It is the duty of journalists to protect the image of society and state. I hope that from now on, we will all act responsibly."

Islam was lodged in Kashimpur Central Women's jail.

The health ministry filed a case against Islam under the draconian 1923 Official Secrets Act that carries harsh penalties, including a possible death penalty.

Reacting to reports of Islam's arrest, UN Secretary-General Antonio Guterres' spokesperson Stephane Dujarric on Tuesday said it is obviously "something concerning.

"Journalists need to be able to do their work free of any sort of harassment or physical threat anywhere around the world. And, obviously, that includes Bangladesh and every other country. I think we have seen the very important work that journalists all around the world have done during the pandemic, and they need to be able to continue that work, wherever they may work," Dujarric said at a regular media briefing at the United Nations headquarters in New York.

Rozina, who earned the reputation of being an investigative journalist, has in recent months published several reports exposing the health ministry's alleged malpractices during the Covid-19 pandemic, drawing public attention.

She also published several reports involving the health sector which included alleged graft in procurement at the health ministry, corruption in doctors' recruitment and how urgent medical equipment for coronavirus treatment was left at Dhaka airport for months.

Several legal experts and senior lawyers said they could not recall any instance when the 1923 Official Secrets Act was used against any journalist.

Journalists' unions and different media platforms have been staging demonstrations in Dhaka and other districts, demanding Islam's immediate release and punitive actions against the officials who "harassed" her.