European Union leaders have voiced their concerns over the US government's increasing unilateral actions, saying global cooperation on pressing issues is crucial.

European Commission President Ursula von der Leyen and European Union foreign policy chief Josep Borrell urged the US on Saturday to reconsider its decision to cut relations with the World Health Organization.

US President Donald Trump said on Friday, "We will be today terminating our relationship with the World Health Organization and redirecting those funds to other worldwide and deserving urgent global public health needs."

In a statement, von der Leyen and Borrell said that "global cooperation and solidarity through multilateral efforts are the only effective and viable avenues to win this battle the world is facing," referring to the fight against the COVID-19 pandemic.

On the same day, Borrell and foreign ministers from France, Germany and the United Kingdom issued a joint statement expressing their regret at the US decision to end the three waivers covering key nuclear projects in Iran under the Joint Comprehensive Plan of Action.

The statement called the JCPOA "a key achievement of the global non-proliferation architecture and currently the best and only way to ensure the exclusively peaceful nature of Iran's nuclear program".

The JCPOA was signed in 2015 between Iran and the United States, China, Russia, France, Germany, the United Kingdom and the EU. The US officially withdrew from the agreement in May 2018 and reinstated sanctions on Iran, triggering an outcry from other partners.

Last month, the foreign ministers of France, Germany, Belgium, Spain, Italy, Finland, the Netherlands, Luxembourg, Sweden and the Czech Republic issued a joint statement voicing their regret over the US decision to withdraw from the Treaty on Open Skies, signed by more than 30 countries in 2002 to bring transparency to military activities.

In the past three years, EU leaders have voiced their opposition to the US withdrawal from the Paris Climate Agreement in 2017, terminating the Intermediate-Range Nuclear Forces Treaty with Russia in August last year, and threatening to end the US-Russia New Strategic Arms Reduction Treaty, which is scheduled to expire in February.

"Very worrying. Highly likely that a new Trump administration will kill off the New START Treaty as well. And that would be the end of strategic arms control built up over many decades," former Swedish prime minister Carl Bildt, now co-chair of the European Council of Foreign Relations, said in a tweet on Sunday.

EU leaders have also been angered by Trump criticizing the EU, supporting the UK's exit from the EU, and waging tariff wars on the EU and its member states.

Last week, German Chancellor Angela Merkel declined Trump's invitation to attend a G7 summit in person in Washington. The US holds this year's presidency of the G7, which also includes Germany, France, the UK, Italy, Canada and Japan.

"The federal chancellor thanks President Trump for his invitation to the G7 summit at the end of June in Washington. As of today, considering the overall pandemic situation, she cannot agree to her personal participation, to a journey to Washington," German government spokesman Stefen Seibert told Politico on Friday.

Trump told the media on Saturday that he plans to hold an expanded G7 meeting in September to include the leaders of Russia, India, Australia and the Republic of Korea.

However, on Monday, UK Prime Minister Boris Johnson, through his spokesman, and Canadian Prime Minister Justin Trudeau opposed the idea of inviting Russia back into the G7 after it was expelled in 2014 from what was then the G8.

David Whineray, a nonresident fellow in the Europe Program at the Washington-based Carnegie Endowment for International Peace, said tensions between the US and the EU could continue, and even grow, regardless of who wins the US presidential election on Nov 3.

He said European diplomats privately concede that transatlantic relations are at their lowest point since the end of the Cold War, including during the Iraq War in 2003.

"Previous US-EU disagreements have been over policies. Today, the very concept and value of transatlantic unity is questioned," he wrote in an article posted on the think tank's website on May 6.

According to Business Insider, a survey last month found that just 2 percent of French people trusted Trump to lead the world, while another poll found that an overwhelming majority of Germans said they had a worse opinion of the US because of the pandemic.