Prime Minister David Cameron and American President Barack Obama have agreed on the need for "an immediate plan" to resolve the eurozone crisis, Downing Street said.
It came in a phone conversation between the two leaders, ahead of the crucial G20 summit in Mexico later this month, where world leaders will again attempt to agree a way through the problems.
Chancellor George Osborne also took part in a "stock-taking" conference call on Tuesday with counterparts from the G7.
Meanwhile, the Government welcomed new European Commission plans to protect taxpayers and avoid future bank bailouts as a "positive step" towards breaking the "too big to fail" culture of the European banking sector.
The contacts come amid mounting fears over Spain's ability to raise funds on international markets at affordable levels.
Mr Cameron is due to visit Berlin today, where he is expected to urge German chancellor Angela Merkel to push for tougher fiscal governance in the eurozone.
In Tuesday night's phone conversation Mr Cameron and Mr Obama "agreed on the need for an immediate plan to tackle the crisis and to restore market confidence, as well as a longer-term strategy to secure a strong single currency", said Number 10.
The Prime Minister has been making clear for some time that it is for the eurozone countries to take "decisive action" to stand behind their currency, said the spokeswoman.
This should involve building an effective "firewall" to prevent contagion spreading, ensuring banks are well capitalised, creating a system of fiscal burden-sharing and enacting a supportive monetary policy across the eurozone.
In Brussels yesterday, EU financial services commissioner Michel Barnier announced the latest plan for EU-wide rules to deal with bank failures, which European Commission president Jose Manuel Barroso described as "an essential step towards banking union in the EU".
Under the proposals, European banks would be obliged to draw up recovery plans setting out measures they would take if their financial position weakened.
They would also have to prepare a "resolution plan" with options for dealing with banks "in critical condition which are no longer viable".
Mr Barnier said the plan would help public authorities intervene "decisively" before bank problems arise - and swiftly if they do.
"The financial crisis has cost taxpayers a lot of money," he said.