British Prime Minister David Cameron addressed European Union leaders on Thursday evening in Brussels on Britain's desire for a looser association with the EU bloc, while leaders of the bloc grapple with an influx of migrants and the prospect of a Greek default.Cameron's move has long been considered as a challenging task persuading other EU members to accept new terms for the United Kingdom before it holds a referendum on membership by the end of 2017. The summit marks the formal start of Britain's latest renegotiation of its ties with Europe, the world's largest economic bloc. "It's the first EU summit where renegotiation of the U.K.'s relationship with the EU is formally on the agenda," Cameron said in remarks released by his Downing Street office. "It will take us another step closer to addressing the concerns that the British people have about the EU and closer to changing the status quo for the better, then giving the British people a say on whether the U.K. should stay in or leave the EU."Before the Brussels summit, Cameron held a series of talks with other European leaders in a bid to secure reforms to the EU that he says are necessary ahead of the referendum. Under pressure from Eurosceptics in his Conservative party and the rise of the anti-EU UKIP party during his first term as prime minister, Cameron in 2013 promised a referendum if he was re-elected. He won a majority seven weeks ago.British Prime Minister Cameron, as part of the Conservative governments' legislative program, demanded structural changes in EU policies on immigration and border control. The proposed plan would reshape Britain's position in the EU, contingent upon the EU leaders' positive attitude toward EU reforms. The plan proposes "controlling migration by making it harder for EU migrants to claim state benefits in Britain, opting out of the EU's commitment to an 'ever closer union' and handing some powers back to national parliaments."Cameron said earlier that he will vote in favor of remaining in the EU if he can secure these changes, which include making it harder for EU migrants to claim state benefits in Britain. Opinion polls suggest so far that the majority of voters in Britain would back staying in Europe. A survey conducted by the Pew Research Center on the British mood over the EU exit shows that 55 percent of U.K. citizens are in favor of remaining part of the EU bloc. Thirty-six percent wants Britain to leave the EU bloc, the poll suggests. Compared to 2013 findings, this marks an increase, as only 46 percent of U.K. citizens favored EU membership in 2013 while 46 percent favored leaving.British opponents of the EU say that the euro is flawed and that the EU is a poorly run elitist project that is slipping far behind the United States and Asia. Britain's allies say leaving the world's biggest trading block would be a foolhardy step that would torpedo Britain's global clout and expose its financial center to rules over which it had no influence.Meanwhile, during a royal visit to Germany, Queen Elizabeth II stressed the need for unity in Europe saying that "We know that division in Europe is dangerous and that we must guard against it in the west as well as in the east of our continent. The United Kingdom has always been closely involved in its continent. Even when our main focus was elsewhere in the world, our people played a key part in Europe," the Queen said. British media interpreted the Queen's speech as a political statement addressing Cameron's planned referendum on Britain's EU membership. But, a Buckingham Palace aide quoted by the BBC rejected the interpretation of the queen's words. "This is not about the EU. The queen is apolitical. She would never make a political point," the aide said, adding that the queen had been referring to risks of wider differences dividing the continent. The queen has an impartial role in Britain and rarely makes any public statement that could be interpreted as relating to current political events.