Barack Obama and David Cameron promise not to delay Afghanistan withdrawal Barack Obama welcomes the British PM, David Cameron, during an official arrival ceremony on the South Lawn of the White House. Photograph: Charles Dharapak/AP British and American forces remain on track to pull back from lead combat missions in Afghanistan next year, Barack Obama and David Cameron declared at the White House on Wednesday. The leaders of the countries with the largest number of troops in Afghanistan said the recent violence would not derail their plans to ensure that all combat troops are withdrawn by the end of 2014. Obama and Cameron's display of unity on Afghanistan came during a visit in which the US president pushed the boundaries of protocol, bestowing on Cameron a lavish state dinner at the White House and issuing his most enthusiastic endorsement yet of the "rock solid" Anglo-American special relationship. The purpose was clear: Obama wants to work closely with Britain and other European allies as he prepares for what may be the main foreign policy crisis of his presidency - a possible Israeli attack on Iran. After a morning of talks at the White House, Obama and Cameron appeared at a joint press conference in the Rose Garden. On Afghanistan, the US president said: "Our forces are making very real progress: dismantling al-Qaida; breaking the Taliban's momentum; and training Afghan forces so that they can take the lead and our troops can come home." Obama, who has pledged to withdraw the remaining 23,000 "surge" troops he sent to Afghanistan by this September, said that the Nato summit in Chicago in May would agree the timetable for the transition to Afghan forces. The president said: "At the upcoming Nato summit in my hometown of Chicago, we'll determine the next phase of transition. This includes shifting to a support role next year, in 2013, in advance of Afghans taking full responsibility for security in 2014. We're going to complete this mission, and we're going to do it responsibly. But Obama said that Nato would not be turning its back on Afghanistan. Nato will maintain an enduring commitment so that Afghanistan never again becomes a haven for al-Qaida to attack our countries. The two leaders are determined to stick to the timetable agreed in outline at a Nato summit in 2010. Obama needs to go into November's presidential election saying he has ended two wars started under his predecessor, George Bush. Cameron is dealing with rising opposition to the Afghan war. But Obama said he is under no illusions about the challenge ahead as he said there had to be a political strategy in which Afghanistan's different ethnic groups recognise that they should end 30 years of war. "We can't be naïve about the difficulties that are going to be involved in getting there," he said. But if we maintain a steady, responsible transition process, which is what we've designed, then I am confident that we can put Afghans in a position where they can deal with their own security. Cameron said that great progress has been made in recent years but he acknowledged that Afghanistan would still be a deeply troubled country when Nato forces leave. We will not give up on this mission because Afghanistan must never again be a safe haven for al-Qaida to launch attacks against us. We won't build a perfect Afghanistan, although let's be clear, we are making some tangible progress with more markets open, more health centres working, more children going to school, more people able to achieve a basic standard of living and security. The two leaders used their joint press conference to issue a strong message to Syrian president Bashar al-Assad that his days are numbered. Obama said: "Just as the regime and security forces continue to suffer defections, the opposition is growing stronger. I'll say it again: Assad will leave power. It's not a question of if, but when. And to prepare for that day, we'll continue to support plans for a transition to support the legitimate aspirations of the Syrian people. Cameron went further as he gave voice to what has so far been a private British position - Assad will face the same fate as Hosni Mubarak, the former Egyptian president who is now on trial in Egypt, or Muammar Gaddafi, the former Libyan leader killed by his own countrymen, if he refuses to relinquish power. The PM said: "What we want is the quickest way to stop the killing. That is through transition rather than revolution or civil war. But if Assad continues, then civil war or revolution is the inevitable consequence. So we will work with anyone who is ready to build a stable, inclusive, and democratic Syria for all Syrians. Obama used his meeting with Cameron to deliver a strong endorsement of what he called "rock solid" Anglo-American special relationship, declaring it "stronger than ever." Obama wants to work closely with Britain and other European allies as he deals with an increasingly tense situation with Israel and Iran. He hopes the Europeans will help in three ways - maintaining diplomatic and economic pressure on Iran; playing a key role in negotiations on that country's nuclear programme; and not abandoning the US if it becomes involved in military action against Iran. Obama and Cameron made clear their focus now is on negotiations and sanctions and not military action. Obama said: "We are fully united. We are determined to prevent Iran from acquiring a nuclear weapon. We believe there is still time and space to pursue a diplomatic solution, and we're going to keep coordinating closely with our P5-plus-1 partners. Permanent members of the UN security council plus Germany. At the same time, we're going to keep up the pressure, with the strongest US sanctions to date and the European Union preparing to impose an embargo on Iranian oil. Tehran must understand that it cannot escape or evade the choice before it - meet your international obligations or face the consequences. Obama and Cameron did acknowledge that Britain and the US often take different paths when they were asked about their different responses to the economic crisis. Obama has faced criticism from some Republicans for adopting an overly Keynesian approach which relies on billions of dollars in fiscal stimulus. Cameron is criticised by the Labour party for eschewing Keynesianism as he adopts a rapid deficit reduction plans and relies on monetary policy to stimulate the economy. The president admitted that Britain and the US have adopted different approaches. The US and Great Britain are two different economies in two different positions. Their banking sector was much larger than ours. Their capacity to sustain debt was different than ours. As a consequence, each of us are going to be taking different strategies and employing different timing. Cameron echoed these comments and said Britain and the US had similar fundamental goals. There are differences, as Barack has said, between the states of the two economy and the circumstances we face. But we're both trying to head in the same direction of growth and low deficits. Actually, if you look at the US plans for reducing the deficit over coming years, in many ways they are actually steeper than what we're going to be doing in the UK. Cameron is often criticised by Labour for failing to follow Obama's lead. But he says that there are two different. First, the US dollar is a reserve currency which means it is safer for the US to borrow. Second, the fiscal stimulus measures in response to the downturn on both sides of the Atlantic have both worked out at about 1% of GDP. Obama appears to be taking greater action because the US does not have "automatic fiscal stabilisers" - the fiscal mechanism in the UK that makes up the differences as tax receipts fall and welfare bills rise in a recession.