[LONDON] US Secretary of State John Kerry flew to Brussels and London on Monday to urge British and European leaders not to allow anger to poison their divorce proceedings.
Washington was dismayed by last week's "Brexit" referendum vote to quit the European Union, which sent shockwaves through world markets, but insists its ties with Britain and the EU remain strong.
Scrambling to adjust to the now uncertain Western geopolitical map, US officials say they have no solution themselves to the political crisis in London and Brussels.
But Mr Kerry, as he met Britain's outgoing prime minister David Cameron and EU Commission chief Jean-Claude Juncker, urged both parties to negotiate the split amicably.
"It is absolutely essential that nobody loses their head, nobody goes off half-cocked, people don't start ginning up scatterbrain or revengeful premises," he said in Brussels.
Some European leaders have suggested that the Union take a tough stance on Britain as it negotiates an exit from the 28-member bloc to dissuade others from following suit.
But Mr Kerry reminded officials in both Brussels and London that the Western allies still have too much at stake in terms of economic and political stability to risk division.
"Yes, the EU and UK relationship will now change," Mr Kerry told reporters at the British Foreign Office in London after talks with Foreign Secretary Philip Hammond.
"But what will never change is that we are strongest when we stay together as a trans-Atlantic community and find the common ground rooted in the interests and values of freedom, open markets equality and tolerance."
Mr Kerry said that Washington hopes that both Britain and the European Union remain strong after Brexit, but did not hide US disappointment at British voters' decision.
"The voice that Britain will speak with will continue to be the powerful voice of an ally that has worked with us on so many issues through the years," he said.
"But that doesn't mean we won't miss that voice within the context of the EU," he continued.
"I personally will regret that Britain is not going to be at that table when there is a US-EU dialogue."
Mr Hammond, who campaigned alongside Mr Cameron and some of his cabinet colleagues for Britain to stay in Europe, echoed this regret but said he hoped for a gentle split.
He denied that Britain had been diminished as a global power, but admitted that the government would now have to "redouble our efforts" to project that influence.
"You won't see us shrinking back, if anything you'll see us resolving to be even more present, to be even more a force in action on the global stage," he said.
"I hope that this will be an amicable discussion," he said of the negotiation that will take place between Mr Cameron's successor and Brussels on Britain's terms of exit.
"But the wound is quite raw," he warned, admitting that Britain's erstwhile EU partners had a "genuine fear of contagion" that could lead more countries to leave.
Mr Kerry met Mr Juncker and EU foreign policy chief Federica Mogherini in Brussels, then Mr Hammond and Mr Cameron in London, before setting off back to Washington.
For more coverage of the EU referendum, visit bt.sg/BrexiT