The US Embassy in Iraq on Wednesday urged all American citizens in the country to leave as soon as possible or shelter in place until an opportunity to depart arises.

"US citizens in Iraq are strongly encouraged to depart the country as soon as they are able to do so, or to shelter in place until conditions for departure are safe. Stock up on food, water, medication and other essential supplies," the embassy's website statement reads.

Earlier, the State Department ordered non-essential embassy staff to leave the country due to security threats.