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.
Sydney Airport flights disrupted due to air traffic controller shortage
A shortage of air traffic controllers has caused flight cancellations and major delays at Sydney Airport on Friday morning, the federal agency responsible for managing Australia's air traffic said.
Philippine firefighters enter charred ferry as search continues for dozens missing
Philippine firefighters on Friday managed to board a burned-out ferry more than a day after the ship caught fire on its way from Manila to the western province of Palawan, killing five people and leaving more than 80 missing.
Modi, Putin hold talks in New Delhi on trade, defence
Indian Prime Minister Narendra Modi and Russian President Vladimir Putin began talks in New Delhi on Friday, their second meeting in two weeks, that is expected to focus on trade, energy and defence ties between the two countries, which have long been friends.
More US lawmakers seek AI rules after Anthropic researchers warn of extinction
Growing numbers of US lawmakers are calling for new rules to govern AI systems after dire warnings from two Anthropic researchers that rapidly progressing artificial intelligence could lead to the extinction of the human race in the not-too-distant future.
Fire in rebel-held east Congo kills 24 schoolchildren
A fire in Congo's rebel-controlled city of Bukavu killed at least 24 children as it destroyed two schools and burned down around 300 wooden houses, an official from the rebel administration told Reuters on Thursday.
Sheikh Abdullah bin Zayed Al Nahyan, Deputy Prime Minister and Minister of Foreign Affairs, has held phone discussions with his counterparts in Kuwait and Bahrain, national news agency Wam reported on Friday.
The UAE has announced plans to invest 40 billion euros in Germany, targeting key sectors including industry, advanced technology, artificial intelligence, digital infrastructure and energy.
UAE President His Highness Sheikh Mohamed bin Zayed Al Nahyan and German Chancellor Friedrich Merz have witnessed the announcement of a series of agreements, memoranda of understanding and letters of intent aimed at expanding cooperation.
