LONDON (AFP) - The conflict in Afghanistan is deteriorating in some ways and will not remain winnable indefinitely, the top US military commander in the country warned Thursday. General Stanley McChrystal added that forces would be in a much stronger position once US President Barack Obama decides on troop levels in Afghanistan, while saying that it would be wrong to rush to make a decision. The situation is serious and I choose that word very, very carefully ... neither success nor failure can be taken for granted, said McChrystal, who has asked for up to 40,000 more troops to fight the Taliban. The situation is in some ways deteriorating but not in all ways, he told the International Institute for Strategic Studies (IISS) thinktank in London. Waiting does not prolong a favourable outcome. This effort will not remain winnable indefinitely. He reportedly wants up to 40,000 more US troops in Afghanistan. The US general said Obama led talks in the White House this week very effectively but declined to give any further details on the decision-making process. I think that is a necessary process we go through so we come to a clear decision... Once he makes that decision I think well be in a much stronger position, he said. Asked if he was worried that the political debate was holding up military action, he said: I think the more debate we have the healthier this is going to be. I dont think we have the luxury of going so fast we make the wrong decision, he added. Top US military leaders support sticking with the current strategy in Afghanistan instead of a smaller-scale mission focused on hunting down Al-Qaeda figures, the Pentagon said on Wednesday. The commander of the NATO-led mission in Afghanistan, General Stanley McChrystal, the head of the regional Central Command, General David Petraeus, and the top US military officer, Admiral Mike Mullen, all endorse the counter-insurgency strategy now being carried out in the Afghan war, press secretary Geoff Morrell said. I think, clearly, the senior military representatives who have equities here-General McChrystal, General Petraeus and the chairman-have all stated publicly their view of counter-insurgency as the preferred method of dealing with the threat we face in Afghanistan, Morrell told a news conference. The three officers all joined a high-powered review of war strategy at the White House on Wednesday as President Barack Obama weighs sending yet more troops. Peter Galbraith, sacked as deputy UN special envoy to Afghanistan, said his dismissal sends a terrible signal about the bodys commitment to a fraud-free election for the countrys next president. The German government is considering increasing the upper limit of its troop contingent in Afghanistan to 7,000 from the current 4,500, Deutschlandfunk public radio reported on Thursday.