北约领导人星期五将在葡萄牙首都里斯本会面，讨论北约在后冷战时代的新使命、阿富汗战争、以及北约与俄罗斯的关系等问题。
北约预计会提出一个新的“战略概念”来对付全球性的安全担忧，这些担忧与北约11年前上一次修订它的使命时已经发生了巨大的变化。
这个有28个成员国的西方军事联盟新的关注重点是由美国前国务卿尔布莱特领导的一个专家小组起草的。
前美国驻北约大使罗伯特.亨特说，过去十年间，北约的安全挑战从领土争端到全球恐怖主义、越境犯罪以及网络威胁的演变，影响了北约新的关注重点。
阿富汗也将成为这个为期两天峰会的优先议题。
美国总统奥巴马预计将列出一个为期四年的撤军计划，定于明年开始将13万北约部队撤出阿富汗，而且将逐步把控制权交给阿富汗安全部队。
NATO is expected to unveil a new "strategic concept" to address global security concerns that have drastically shifted since the alliance last revised its mission 11 years ago.
The new focus of the 28-member Western military alliance was drafted by a group of experts led by former U.S. Secretary of State Madeleine Albright.
A former U.S. ambassador to NATO, Robert Hunter, says the evolution of security challenges over the last decade from territorial disputes to global terrorism, cross-border crime and cyber threats has shaped the new focus of the organization.
Afghanistan also will top the agenda of the two-day summit.
U.S. President Barack Obama is expected to outline a four-year withdrawal plan of 130,000 NATO troops, which is set to begin next year and will gradually hand over control to Afghan security forces.
