US President George W Bush has said he wants to see a "strong European Union" working with America to spread freedom and democracy.
Relations have improved dramatically since the Iraq invasion
His comments came after a meeting with EU leaders at the White House.
The US-EU summit comes days after an acrimonious EU meeting in Brussels which saw attempts to reach a deal on the bloc's budget end in failure.
UK Prime Minister Tony Blair has called for reform of how the EU spends its money, including cuts in farm spending.
Mr Blair said he was right to refuse to give up the UK's 4.4bn euro (£3bn) annual rebate without wider reforms, telling parliament that it made no sense for the EU to spend 40% of its budget on agricultural subsidies.
The BBC's Jonathan Beale in Washington says the Bush administration is concerned that the EU's internal dispute will lead to a period of introspection.
He adds that President Bush wants the EU to continue the process of accepting new members.
"The United States continues to support a strong European Union as a partner in spreading freedom and democracy and security and prosperity throughout the world," Mr Bush said.
"My message to these leaders and these friends is that we want a Europe strong, so that we can work together to achieve important objectives and important goals.
"One of those important objectives and important goals is the advance of freedom in order to spread peace."
The two sides are expected to announce further co-operation on trade, though not over their dispute on subsidies to the aircraft manufacturers Boeing and Airbus.
Progress has also been made on immigration controls. The US has agreed to postpone its requirement for Europeans to carry biometric passports for at least another year.
Our correspondent says that overall, US-EU relations have improved dramatically since their row over Iraq.
But he adds that there is now the uncertainty over Europe's future direction.