FALMOUTH, England -- The Group of Seven leaders aim to end their first summit in two years with a punchy set of promises Sunday, including vaccinating the world against coronavirus, making huge corporations pay their fair share of taxes and tackling climate change with a blend of technology and money.

They want to show that international cooperation is back after the upheavals caused by the pandemic and the unpredictability of former U.S. President Donald Trump. And they want to convey that the club of wealthy democracies — Canada, France, Germany, Italy, Japan, the United Kingdom and the United States — is a better friend to poorer nations than authoritarian rivals such as China.

But it was uncertain how firm the group’s commitments will be on coronavirus vaccines, the economy and the environment when the leaders issue their final communique. Also unclear was whether all of the leaders would back the United States’ call to chastise China for repressing its Uyghur minority and other abuses.

U.K. Prime Minister Boris Johnson, the summit's host, wanted the three-day meeting to fly the flag for a “Global Britain,” his government's initiative to give the midsized country outsized influence when it comes to global problem-solving.