On Tuesday the U.S. embassy authorised the voluntary evacuation of non-essential staff.

Mr Cunliffe said the police had indicated non-essential staff could use their judgement.

The US embassy has ordered home all families and non-essential staff.

As a result, the United Nations raised its security level and relocated non-essential staff.

Many firms have already removed all non-essential staff during the unrest of recent years.

Meanwhile, the United Nations said it would withdraw all non-essential staff out of the country.

Mining firms have repatriated some non-essential staff but have said operations are proceeding as normal.

Earlier, BHP had said it would remove non-essential staff from its Shenzi and Neptune oil platforms.

Royal Dutch Shell evacuated about 360 non-essential staff from the eastern Gulf the past two days.

Nervous of more turmoil, the US embassy ordered non-essential staff and their families to leave Madagascar.

Meanwhile, Exxonmobil has withdrawn non-essential staff from its LNG Project operations in Hela amid increased security risks.

Good ideas include not having non-essential staff in your home, and not subjecting such staff to mass transit.

The United States ordered non-essential staff to leave Yemen in April after an attack on a residential compound.

Two other big British lenders told Reuters they will also likely reverse recent return-to-work moves for non-essential staff.

Many businesses and government departments, including the Department of Home Affairs, ordered non-essential staff to stay home, media reported.

The US is ordering all non-essential staff in the embassy in Havana to leave, along with all family members.