World leaders at a G7 video summit told Donald Trump that medical firms must share and coordinate research on coronavirus vaccines rather than provide products exclusively to one country.

The US president has been accused by German political leaders of trying to buy exclusive US access to vaccines being prepared by a German firm, CureVac laboratory.

The German firm and the US have denied the move, but the episode, first reported in the German press at the weekend, has symbolised fears that Trump does not have an instinct to cooperate with other world leaders to fight the virus.

There had not been any sign of a coordinated international response to the pandemic until Monday’s G7 call, in contrast to the 2008 financial crash. Many countries have opted for unilateral monetary and health initiatives, sometimes in competition with each other.

After the one-hour call, members of the G7 issued a joint statement of solidarity, saying: “By acting together, we will work to resolve the health and economic risks caused by the Covid-19 pandemic and set the stage for a strong recovery of strong, sustainable economic growth and prosperity.”

EU council president Charles Michel implicitly criticised any go-it-alone move on vaccines, saying: “We expressed a very strong political will that we considered it very important to work together to develop vaccines and therapies.”

The EU commission president, Ursula von der Leyen, added that the G7 had learned lessons from the previous Ebola epidemic on the need to set up a platform of renowned scientists, known as CEPI – Coalition for Epidemic Preparedness Innovation – to share research.

She also said it was “of the utmost importance that neighbouring countries harmonise their measures so that there is the same strong message to the people that the member states are conveying, because that then increases the certainty of the people”.

The UK has until now largely been out of line with mainland European states on its response to the crisis, making fewer announcements – until Monday’s dramatic moves – on social distancing.

Some countries, notably Singapore, have even accused the UK of abandoning any effort to combat the virus. Boris Johnson spent some part of the video conference explaining the rationale behind the UK approach.

No major new economic measures were announced at the end of the meeting, but White House economic adviser Larry Kudlow said “they all want to do whatever it takes”. Ahead of the call, the US Federal Reserve on Sunday had already cut interest rates to near zero and announced plans for $700bn (£570bn) in bond purchases.

Boris Johnson implied further demand-side measures may be in the pipeline, saying: “There is a widespread agreement among colleagues in the G7 that we are going to need to make sure everybody has access to liquidity and that if we do things jointly, then I think that the global markets will understand that we’re all operating in the same sort of fiscal framework and I think we’ll be much more successful that way.”

The difficulty is that economic activity is collapsing with every move to curtail movement and social contact.

The idea of a summit at leader level, bringing together the main western economies and Japan, was proposed last week by Emmanuel Macron, the French president.

Since then, the crisis has spiralled and the major economic interventions by the US Federal Reserve, coupled with steps by the Japanese central bank, had failed to reassure markets, leaving world leaders to hold their talks against the backdrop pf another round of crashing stock markets and figures showing the spread of virus in Europe is now worse than in China.

The EU largely used the summit to inform the other states it was closing its external borders for a month to all countries outside the Schengen visa area. EU finance ministers met separately.

The G7 consists of Canada, France, Germany, Italy, Japan, the UK and the US.

The US is the current chair of the G7, but Trump’s leadership on coronavirus has been haphazard and the US president, who has an inherent dislike of multilateral solutions, had to be coaxed into holding the summit.

Robin Niblett, the director of the Chatham House thinktank, had warned the epidemic represented a make-or-break moment for international cooperation.

He said: “The disjointed global economic response to Covid-19, with its enormous ramifications for global prosperity and economic stability, has blown into the open the urgent need for an immediate reaffirmation of international political and economic cooperation.”

But Kudlow insisted the call had been worthwhile, and said the summit had expressed solidarity with Japanese hopes that the Olympics will still be able to go ahead this summer.

Trump did not consult with European leaders before he imposed the US travel ban last week and the weekend revelation that the US sought to secure exclusive access to a potential vaccine by offering a lucrative contract to CureVac laboratory in south-west Germany has infuriated public opinion.

“German researchers play a leading role in the development of medicines and vaccines and we cannot allow others to seek the exclusivity of their results,” the German foreign minister, Heiko Maas, said.

US officials insisted German resentment was misplaced and Washington had spoken to more than 25 pharmaceutical companies and assured that “any solution that comes up will be shared with the rest of the world”.

The EU is meanwhile taking steps to ban the export of medical masks, gloves and protective clothing outside the bloc without prior authorisation. “We need to share this equipment within the European Union,” said Von der Leyen.

The G20 – a wider group of economic powers including China, India, Russia, South Africa and South Korea – is also to be consulted and is seen as a more natural body to address the crisis.

Scott Morrison, the Australian prime minister, said he had been in discussion with his Indian counterpart, Narendra Modi, to hold such a meeting.

In total, about 50 countries have announced restrictive measures – ranging from the ban on entry into their territory, such as Israel or the US, to health checks or quarantines.

Almost all countries are facing difficult choices over demand stimulus, protecting laid-off workers, overstretched hospital services, the closure of public spaces and the value of widespread testing.

South Korea, seen as a leader in combating the virus, has offered to brief the world leaders either at G7 or G20 level on how it believes widespread testing for the virus is critical to its containment.

South Korea’s president, Moon Jae-in, said on Monday he was increasingly confident the country would overcome the coronavirus as the rate of new infections continued to drop, although authorities noted another large cluster had emerged in the greater Seoul area.

There are tentative signs that the scale of the crisis is leading some traditional foes to see if there is scope for cooperation. Iranian officials, for instance, had a rare conversation with their counterparts from the United Arab Emirates and world leaders will have to confront at some point whether to lift sanctions in Iran to help the country fight the virus, where the death toll is 853, since the world will not be safe from the disease unless it is eradicated worldwide.

The main G7 leaders’ summit is due to be held at Camp David, the US presidential retreat, in June, but the prospect of a physical gathering of leaders going ahead must now be in the balance.

The G20 summit is not due to occur until November in Riyadh, although lower-level ministers are due to meet throughout the year. A range of other summits have been cancelled, including a meeting in Istanbul that had been due to take place on 17 March to discuss the crisis in Idlib.