The United States, United Kingdom and Germany have rejected allegations that their governments financed protests that have shaken the Balkan country's populist government.
The embassies of the allied countries issued a joint statement that described the accusations as "damaging".
"These claims do not reflect our partnership with Serbia," they said.
The statement came a day after Serbian Prime Minister Ana Brnabic criticised the alleged foreign backers of activist groups that organised weeks of environmental demonstrations.
She accused the sources of alleged outsider influence of what she described as "hypocrisy".
Brnabic made the allegations while announcing on Thursday that ecological concerns prompted her government to scrap a lithium mining project the Rio Tinto company planned to undertake in western Serbia.
The government's decision was seen as a bid to defuse the protests ahead of Serbia's general election in April.
Brnabic described the demonstrations as political and said that foreign organisations were financing the environmental and other groups critical of the government with an aim to weaken the populist administration of Serbian President Aleksandar Vucic.
In their statement, the UK, German and US strongly denied the prime minister's assertions.
"Without reservation, we reject any suggestion that our countries, or the organizsations through which we provide technical assistance and support, are funding or directing actions specifically targeting the Serbian government or any of its policies," the three embassies said in the statement.
"This includes the financing of protests."
The embassies said their countries have been among Serbia's "most generous and reliable partners and friends, providing assistance funding totalling well over 3 billion euros" ($A4.7 billion).
"We are clear and transparent about this assistance and our goals: to support reform, good governance, democratic development, green transition and prosperity," the statement added.
"Significant amounts of this assistance is provided to the Serbian government or delivered in co-operation with the Serbian government and its agencies."
Serbia is formally seeking membership in the European Union but the country has also fostered close ties with Russia and China.
Australian Associated Press
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