London (CNN) -- The United States and Britain remain committed to supporting the so-called "Arab spring" -- the series of uprisings sweeping the North African and Middle East region -- and turning up the heat on embattled Libyan leader Moammar Gadhafi, President Barack Obama said Wednesday.
His comments came after meetings with British Prime Minister David Cameron.
Obama said he intends to discuss support for democracy movements at the upcoming G8 summit Thursday.
"We will continue to strongly oppose the use of violence against protesters," said Obama at a joint news conference following talks with Cameron at his office, 10 Downing Street.
"That is one of the reasons we are working together in Libya," Obama said. "I do think we have made enormous progress in Libya. We have saved lives. Gadhafi and his regime need to understand there will not be a letup in the pressure we are applying."
The two men spoke before Obama was scheduled to address both houses of Britain's Parliament later Wednesday, the second day of a state visit blending pomp, ceremony and diplomacy. Obama's speech was described by a top aide as an anchor for his European trip.
The two leaders discussed a wide range of issues that included policy in Afghanistan and Pakistan and the Israel-Palestinian conflict.
Obama said America's relationship with Britain is "the strongest it has ever been" and said the two nations were committed to working together on global economic recovery and fighting the war on terror.
Cameron said the U.S. killing of al Qaeda leader Osama bin Laden was "a strike right at the heart of international terrorism" and that Britain and the United States must work closely with Pakistan in the future.
"We can defeat al Qaeda," Cameron said.
Queen Elizabeth II hosted Obama and his wife Michelle at a state dinner Tuesday night, an event marred by a slight snafu when an orchestra interrupted Obama's toast to his hostess by playing "God Save the Queen."
"To Her Majesty the Queen," Obama began, but the orchestra -- apparently thinking the president had concluded -- started playing the British anthem.
Obama continued with his toast, speaking over the music in citing the special relationship between the British and American people and quoting William Shakespeare's tribute to "to this blessed plot, this earth, this realm, this England" from "Richard II."
Obama is in the middle of a six-day, four-nation trip to Europe that began in Ireland and will continue with stops in France and Poland.
The president and first lady toured Buckingham Palace and visited Westminster Abbey Tuesday, where crowds that had gathered along the roads outside cheered their arrival.
Ben Rhodes, the deputy national security advisor for strategic communications, said Obama would reaffirm that the U.S.-British alliance and NATO are "the cornerstone of global security and the extension of the democratic values that we share."
"The United States and the United Kingdom, along with our allies, are the ones who shoulder particular burdens for global security," Rhodes told reporters. "We see that in Afghanistan. We see that in our efforts against al Qaeda. We see that of course today in Libya."
Cameron talked up the two countries' closeness the night before the Obama visit officially began, calling the relationship "essential" and saying there is an "incredible alignment of views" between 10 Downing Street and the White House.
On a less formal note, Obama also joined Cameron in playing table tennis against two students during a visit to a local school. No details on the final score were made public, but the students won handily.