U.K. Prime Minister Boris Johnson became the first European leader to speak with U.S. President Joseph Biden since his inauguration in a phone call that focused on ways to strengthen bilateral ties, collective defense and fight climate change.

Biden pledged to work closely with Johnson as the U.K. hosts both the G-7 and the United Nations Climate Change conference this year, according to a statement from the White House.

Johnson “warmly welcomed” Biden’s decision to have the U.S. rejoin the Paris Agreement on reducing greenhouse emissions, abandoned by President Donald Trump. He also praised Biden for renewing U.S. support for the World Health Organization and the Covax program to support the equitable distribution of Covid-19 vaccines.

The U.K. statement also mentioned discussions of “the benefits of a potential free trade deal between our two countries.” Reaching a new trade accord with the U.S. now that the U.K. has exited the European Union is a top priority for Johnson. The U.S. statement didn’t mention a discussion of trade.

The two leaders also expressed their support for the North Atlantic Treaty Organization and for shared values to promote human rights, according to the U.K. statement.