It follows reports that President Trump was outraged by comments made by Mulvaney during the Ukraine corruption saga.
The allegations of abuse of power over the Ukraine incident led to impeachment proceedings against President Trump.
Mulvaney's departure has been on the cards for the last few weeks.
Mr Mulvaney is to become US special envoy to Northern Ireland, while North Carolina lawmaker Mark Meadows has been appointed to take over his former position.
Saudi Arabia intercepts and destroys drone in Mecca region
Saudi Arabia's air defences intercepted and destroyed a drone from the Houthis targeting the Mecca region on Friday morning.
Six feared dead in helicopter crash in Indian Himalayan state, media report
Six people were feared dead in a helicopter crash in the Indian Himalayan state of Uttarakhand on Friday, television channels reported, adding that bad weather was suspected to be the cause.
Residents leave Russian-occupied Oleshky under truce brokered by Melania Trump
Starving and exhausted residents of a Russian-held town in southern Ukraine were evacuated by bus on Friday as part of a joint relief operation by the opposing sides, the first of its kind in four years and eight months of war.
Four killed as Italian helicopter in EU mission in Bosnia crashes
Four people died and 11 were injured after an Italian military helicopter crashed in Bosnia and Herzegovina on Thursday, Italy's Defence ministry said.
The UAE has confirmed that the oil spill from the tanker GEM No. 2 has been contained, as authorities continue environmental remediation efforts along affected coastlines.
His Highness Sheikh Mohammed bin Rashid Al Maktoum, Vice President and Prime Minister of the UAE and Ruler of Dubai, has reviewed plans and implementation stages of the AED 500 million Arab Reading Challenge Endowment project, which will be developed by Sobha Realty in Dubai.
The UAE's Military Attorney-General has ordered the referral of a number of defendants to the Military Criminal Court over allegations of abusing official authority to unlawfully obtain exemptions from national and reserve service.
