Washington, Mar 20 (IANS): The US State Department has raised travel advisory to Level 4, which instructs its citizens to avoid all international travels amid the COVID-19 outbreak.

"In countries where commercial departure options remain available, US citizens who live in the US should arrange for immediate return to the United States, unless they are prepared to remain abroad for an indefinite period," Xinhua quoted theo the US State department as saying on its travel advisory website.

Level 4, known as "Do Not Travel", is the highest warning of the travel advisory. The State Department issued the Level 3 travel advisory last Wednesday, calling on US citizens to reconsider travel abroad, Xinhua reported.

A Politico report said that the move might be unprecedented. "Several current and former US diplomats, some of them with several decades of experience, said they do not recall such a travel advisory ever being issued in the past," according to the report.

There are several reports on US citizens abroad who are unable to return to the country. The New York Times reported Thursday that a lot of American travelers stranded in Morocco and received limited help from the US embassy.

The Trump administration has adopted a series of entry measures recently. The White House announced Wednesday that the US-Canada border would be closed to nonessential travel. Besides, US travel restrictions against European countries have also come into force.

The announcement came amid the rapid spread of COVID-19 across the US. According to the latest update by Johns Hopkins University, there are currently more than 11,000 confirmed cases and 157 deaths related to the novel coronavirus in the country.