US President Barack Obama speaking ahead of Nato’s summit says the alliance must use its resources more effectively in Afghanistan.With Afghanistan the focus of discussions, French President Nicolas Sarkozy said he was fully behind the new US policy. ‘‘We completely support the new American strategy in Afghanistan. We are ready to do more on the police plan, on helping the economy and creating a state structure in Afghanistan,’‘ Sarkozy said. Obama also warned al-Qaeda posed more of a risk to Europe than the US. “It’s probably more likely that al-Qaeda would be able to launch a serious terrorist attack in Europe than in the US because of proximity. This is not an American mission this is a Nato mission. France has always understood that and for that I’m very grateful” Today’s trip marks Obama’s first official visit as US president to continental Europe.