International Development Secretary Douglas Alexander, in a speech in Washington on Thursday, said while Britain stood beside the United States in fighting terrorism, isolationism did not work in an interdependent world.
In the 20th century a country's might was too often measured in what they could destroy. In the 21st, strength should be measured by what we can build together, Alexander said, in comments interpreted by British media as signaling a change in the British government's relationship with Washington.
A spokesman for Brown denied the speech marked any turnaround in policy and said the interpretation put on Alexander's words by the media was quite extraordinary.
Brown told BBC radio he would continue to work closely with the U.S. administration.
We'll not allow people to separate us from the United States of America in dealing with the common challenges we face around the world, he said, when asked about Alexander's words.
Washington has been watching Brown's new government for signs of any policy change after years of close ties under his predecessor Tony Blair.
Brown took over last month with promises of change to woo back voters after 10 years of his Labour Party's rule and in particular to draw a line under the unpopular Iraq war. Blair's closeness to Washington was unpopular with many Britons.
Alexander said in the speech at the Council of Foreign Relations that nations must form new alliances not just to protect us from the world but ones which reach out to the world.
He later told BBC radio Britain's relationship with Washington was important, as part of a wider framework.
Gordon Brown has made very clear that he regards a strong relationship with the U.S. as being one of the fundamental bases of his foreign policy, he said.
But he also wants to see strong relationships with our partners within the European Union, and indeed growing and strong relationships with China and India, emerging powers in Asia, Alexander said.
Brown will visit Berlin on Monday and plans to visit Paris and Washington in the coming weeks, his spokesman said.
While few analysts expect Brown to announce an immediate withdrawal of British troops from Iraq, there is speculation the withdrawal may accelerate. Britain has been reducing troop numbers in Iraq and now has about 5,500 in the south.
Additional impetus is coming from the United States, where the House of Representatives voted for the third time on Thursday to bring combat troops out of Iraq. Two previous efforts to set a timetable either died in the Senate or were vetoed by President George W. Bush.
Alexander said in his speech while there were few global challenges that did not require Washington's engagement, countries should work together through organizations like the United Nations to seek shared solutions to the world's problems.
We need to demonstrate by our word and our actions that we are internationalist not isolationist; multilateralist not unilateralist, he said.
There is no security or prosperity at home unless we deal with the global challenges of security, globalization, climate change, disease and poverty. We must recognize these challenges and champion an internationalist approach.
(Additional reporting by Katherine Baldwin)