WASHINGTON (AFP) - US President Barack Obama on Thursday proposed defence spending of $663.7 billion for fiscal 2010, an increase of 1.5 per cent, but projected the costs of wars in Iraq and Afghanistan would decline in the next several years. The new Administration has signalled it hopes to make savings over time through a planned withdrawal of US troops from Iraq and from cuts in expensive weapons programmes - though Obama's budget request did not specify what new weaponry might be scrapped. The President's proposed budget unveiled Thursday seeks $130b for the wars in Iraq and Afghanistan, down from $141.4bn for operations in the current fiscal year. The proposed budget offered a rough forecast that the cost of the war efforts in those countries would drop to about $50b annually in the next several years. The monthly cost of the war in Iraq has already declined from about $10b to $8b in recent months, officials said. The budget request includes $533.7b for the main defence budget, excluding most of the costs of the conflicts in Iraq and Afghanistan, which marks an increase of four per cent compared to the main budget for fiscal 2009. Some war costs were shifted to the main defence budget, defence officials said, but did not offer further details. The proposed military spending will "meet the national security needs of this country," a Pentagon official, speaking on condition of anonymity, told reporters. The president also requested an additional $75.5b to cover war costs for the rest of the current fiscal year, after Congress approved $65.9b for fiscal 2009 before Obama took office. Meanwhile, senior Pentagon officials have had to promise they will keep the details of the US military budget secret as the Defence Department prepares to make tough cuts on weapons programmes, a spokesman said on Wednesday. In an unprecedented move, Defence Secretary Robert Gates asked top military officers and civilian officials to sign non-disclosure forms in which they agree not to reveal deliberations about the politically charged budget. "Everybody who's participating in this process - these are the highest ranking people in this department ... were asked to sign an agreement in which they would agree not to speak to any of the matters that they are working on as part of this budget process," Press Secretary Geoff Morrell told a news conference. "This is highly sensitive stuff involving programmes costing tens of billions of dollars, employing hundreds of thousands of people and - and go to the heart of national security," he said. Members of the Joint Chiefs of Staff were among those required to sign, and Gates himself signed the form, Morrell said. "This is to reinforce the message that indeed this is classified material. These are highly secret discussions. And we should remember that, be mindful of it, and honour it," Morrell said. The non-disclosure forms may carry less legal weight than the strict security clearances already governing top officials and officers. But the Defence Secretary's step may have been designed more as a symbolic message to curb leaks about sensitive budget negotiations, analysts said. Gates is "trying to invoke personal loyalty," said Michael O'Hanlon at the Brookings Institution, a Washington think tank. "Gates is trying to send the message that if you do that (leak) you're actually hurting me and I'll take it as a personal affront and I'm personally asking you not to do it," O'Hanlon told AFP.