US President Donald Trump has withdrawn the US from dozens of international organisations, including many that work to combat climate change.

Nearly half of the 66 affected bodies are UN-related, including the Framework Convention on Climate Change - a treaty that underpins all international efforts to combat global warming.

Groups working on development, gender equality and conflict - areas the Trump administration had repeatedly dismissed as advancing "globalist" or "woke" agendas - are also included.

The White House said the decision was taken because those entities "no longer serve American interests" and promote "ineffective or hostile agendas".

The memorandum was signed on Wednesday following a review, with the White House describing the organisations as "a waste of taxpayer dollars".

"These withdrawals will end American taxpayer funding and involvement in entities that advance globalist agendas over US priorities," it said in a statement.

It added that many of the organisations promoted "radical climate policies, global governance and ideological programs that conflict with US sovereignty and economic strength".

As well as the UN Framework Convention on Climate Change, the US has also withdrawn from the Intergovernmental Panel on Climate Change (IPCC) - the world's leading authority on climate science that pulls together the most respected reports on the science of rising global temperatures.

Sources within the organisation told the BBC that they were concerned about the potential impact of the Trump administration's withdrawal on US scientists involved in producing the body's next set of studies.

The White House has already blocked US scientists attending a meeting in China.

Any restrictions on travel or the participation of US researchers could significantly delay the release of the next set of IPCC reports, including potentially its mitigation report - a key document guiding governments on how to tackle climate change.

Non-UN organisations affected by the US withdrawal include those focused on clean energy co-operation, democratic governance and international security, such as the International Solar Alliance, the International Institute for Democracy and Electoral Assistance and the Global Counter-Terrorism Forum.

Trump has already stripped many multilateral organisations he dislikes of funds and previously rejected the scientific consensus of man-made climate change as a "hoax".

It will take a year for the US to be able to fully withdraw from the UNFCCC - but in reality the US ceased effective participation in the UN's climate change body long ago.

It remains unclear whether the move will be challenged in the US courts, as many campaigners are now urging.

While the US constitution allows presidents to join treaties "provided two thirds of Senators present concur", it does not specify what happens if they were to withdraw. As such, it is uncertain a future president could reverse Trump's decision and opt back in simply by applying.

These latest withdrawals come after the president took the US out of the Paris Climate Agreement for a second time last year, and declined to send a delegation to the COP30 climate summit in Brazil.

The US has also already withdrawn from the World Health Organization, the UN Human Rights Council and the UN's cultural agency, Unesco.

European leaders have criticised this latest decision, warning it would weaken global co-operation.

EU climate commissioner Wopke Hoekstra said the UNFCCC "underpins global climate action" and called the US retreat "regrettable and unfortunate", while the EU's clean transition vice-president Teresa Ribera said the administration showed little concern for the environment, health or human suffering.

A member of a US-based non-profit advocacy group, the Union of Concerned Scientists, described the step as a "new low".

Senior policy director Rachel Cleetus told news agency AFP that it was another sign the administration, which she described as "authoritarian" and "anti- science", was determined to sacrifice people's wellbeing and destabilise global co-operation.