U.S. Secretary of State John Kerry has called British Foreign Secretary Boris Johnson to congratulate him on his new post and to urge "a sensible and measured approach" to the United Kingdom's withdrawal from the European Union.
New Prime Minister Theresa May surprised many on July 13 when she named the controversial Brexit campaigner and sharp-tongued Johnson to be foreign secretary.
The State Department said Kerry and Johnson "agreed that the U.S.-U.K. special relationship is as essential as ever" and pledged to work together. They also agreed to meet next week in Brussels.
German Foreign Minister Frank-Walter Steinmeier called Johnson "a crafty party politician who managed to use the Euroskeptic mood for himself."
But he added that Johnson now must take on "completely different political tasks" and take "foreign-policy responsibility beyond Brexit."
French Foreign Minister Jean-Marc Ayrault said on July 14 that he is not "worried" about Johnson but said he "lied a lot to the British people and now it is he who has his back against the wall."
He added that France needs "a partner with whom I can negotiate and who is clear, credible, and reliable."
Russian President Vladimir Putin's spokesman, Dmitry Peskov, predicted that Johnson would tone down his rhetoric and be "more diplomatic" in his new role.
With his disheveled blond hair and sharp-edged humor, the man known to Britons simply as "Boris" was a controversial choice for conducting sensitive diplomacy with world leaders.
Asked by a reporter whether as foreign secretary he would apologize to U.S. President Barack Obama for once saying the "part-Kenyan" president was biased against Britain because of "an ancestral dislike of the British empire," Johnson said on July 13: "The United States of America will be in the front of the queue."
That quip was an allusion to a comment by Obama during Britain's EU referendum campaign that the country would be at the back of the queue for trade deals with the United States if it voted to leave the bloc.
Johnson also caused consternation in Europe during the campaign by comparing the EU goal of consolidating Europe with those of Adolf Hitler and Napoleon.
And some past comments could prove awkward with whoever becomes the next U.S. president in January 2017. In 2007, Johnson likened Hillary Clinton, the presumptive U.S. Democratic presidential candidate, to "a sadistic nurse in a mental hospital."
More recently, he joked that he feared going to New York because of "the real risk of meeting Donald Trump," the presumptive Republican candidate.
On Russian President Vladimir Putin, Johnson said in his London Telegraph column: "Let's deal with the devil: We should work with Vladimir Putin and [President] Bashar al-Assad in Syria."
"This is the time to set aside our Cold War mind-set. It is just not true that whatever is good for Putin must automatically be bad for the West. We both have a clear and concrete objective -- to remove the threat from [Islamic State]. Everything else is secondary."
In appointing Johnson, May moved Britain's experienced foreign minister, Philip Hammond, to the Finance Ministry, where he will be responsible for working out many of the critical details of Britain's new trade and economic relationship with the EU during Brexit negotiations.
May, who had campaigned for Britain to stay in the EU, appointed two other prominent Euroskeptics and "Leave" campaigners: David Davis to lead the overall effort to exit the EU and Liam Fox as her international trade chief.
The appointments conveyed that while she may have personal qualms about leaving, as prime minister May will be serious about carrying out the public's mandate. She has repeatedly said that "Brexit means Brexit."
But doing it will take time, May told the leaders of France and Germany in a phone call on her first day in office even as French President Francois Hollande repeated his demand for a quick departure.
"The prime minister explained that we would need some time to prepare for these negotiations and spoke of her hope that these could be conducted in a constructive and positive spirit," a May spokeswoman said on July 13.
"We face a time of great national change," the 59-year-old May said. "As we leave the European Union, we will forge a bold new positive role for ourselves in the world. And we will make Britain a country that works not for a privileged few but for everyone of us."